mm/bootmem.c - kernel/msm - Gitiles

 /*
  *  linux/mm/bootmem.c
  *
  *  Copyright (C) 1999 Ingo Molnar
  *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
  *
  *  simple boot-time physical memory area allocator and
  *  free memory collector. It's used to deal with reserved
  *  system memory and memory holes as well.
  */
 #include <linux/init.h>
 #include <linux/pfn.h>
 #include <linux/bootmem.h>
 #include <linux/module.h>

 #include <asm/bug.h>
 #include <asm/io.h>
 #include <asm/processor.h>

 #include "internal.h"

 /*
  * Access to this subsystem has to be serialized externally. (this is
  * true for the boot process anyway)
  */
 unsigned long max_low_pfn;
 unsigned long min_low_pfn;
 unsigned long max_pfn;

 static LIST_HEAD(bdata_list);
 #ifdef CONFIG_CRASH_DUMP
 /*
  * If we have booted due to a crash, max_pfn will be a very low value. We need
  * to know the amount of memory that the previous kernel used.
  */
 unsigned long saved_max_pfn;
 #endif

 /* return the number of _pages_ that will be allocated for the boot bitmap */
 unsigned long __init bootmem_bootmap_pages(unsigned long pages)
 {
 	unsigned long mapsize;

 	mapsize = (pages+7)/8;
 	mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
 	mapsize >>= PAGE_SHIFT;

 	return mapsize;
 }

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

 	if (list_empty(&bdata_list)) {
 		list_add(&bdata->list, &bdata_list);
 		return;
 	}
 	/* insert in order */
 	list_for_each_entry(ent, &bdata_list, list) {
 		if (bdata->node_boot_start < ent->node_boot_start) {
 			list_add_tail(&bdata->list, &ent->list);
 			return;
 		}
 	}
 	list_add_tail(&bdata->list, &bdata_list);
 }

 /*
  * Given an initialised bdata, it returns the size of the boot bitmap
  */
 static unsigned long __init get_mapsize(bootmem_data_t *bdata)
 {
 	unsigned long mapsize;
 	unsigned long start = PFN_DOWN(bdata->node_boot_start);
 	unsigned long end = bdata->node_low_pfn;

 	mapsize = ((end - start) + 7) / 8;
 	return ALIGN(mapsize, sizeof(long));
 }

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

 	bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
 	bdata->node_boot_start = PFN_PHYS(start);
 	bdata->node_low_pfn = end;
 	link_bootmem(bdata);

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

 	return mapsize;
 }

 /*
  * Marks a particular physical memory range as unallocatable. Usable RAM
  * might be used for boot-time allocations - or it might get added
  * to the free page pool later on.
  */
 static int __init reserve_bootmem_core(bootmem_data_t *bdata,
 			unsigned long addr, unsigned long size, int flags)
 {
 	unsigned long sidx, eidx;
 	unsigned long i;
 	int ret;

 	/*
 	 * round up, partially reserved pages are considered
 	 * fully reserved.
 	 */
 	BUG_ON(!size);
 	BUG_ON(PFN_DOWN(addr) >= bdata->node_low_pfn);
 	BUG_ON(PFN_UP(addr + size) > bdata->node_low_pfn);

 	sidx = PFN_DOWN(addr - bdata->node_boot_start);
 	eidx = PFN_UP(addr + size - bdata->node_boot_start);

 	for (i = sidx; i < eidx; i++)
 		if (test_and_set_bit(i, bdata->node_bootmem_map)) {
 #ifdef CONFIG_DEBUG_BOOTMEM
 			printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
 #endif
 			if (flags & BOOTMEM_EXCLUSIVE) {
 				ret = -EBUSY;
 				goto err;
 			}
 		}

 	return 0;

 err:
 	/* unreserve memory we accidentally reserved */
 	for (i--; i >= sidx; i--)
 		clear_bit(i, bdata->node_bootmem_map);

 	return ret;
 }

 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
 				     unsigned long size)
 {
 	unsigned long sidx, eidx;
 	unsigned long i;

 	/*
 	 * round down end of usable mem, partially free pages are
 	 * considered reserved.
 	 */
 	BUG_ON(!size);
 	BUG_ON(PFN_DOWN(addr + size) > bdata->node_low_pfn);

 	if (addr < bdata->last_success)
 		bdata->last_success = addr;

 	/*
 	 * Round up the beginning of the address.
 	 */
 	sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
 	eidx = PFN_DOWN(addr + size - bdata->node_boot_start);

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

 /*
  * We 'merge' subsequent allocations to save space. We might 'lose'
  * some fraction of a page if allocations cannot be satisfied due to
  * size constraints on boxes where there is physical RAM space
  * fragmentation - in these cases (mostly large memory boxes) this
  * is not a problem.
  *
  * On low memory boxes we get it right in 100% of the cases.
  *
  * alignment has to be a power of 2 value.
  *
  * NOTE:  This function is _not_ reentrant.
  */
 void * __init
 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
 	      unsigned long align, unsigned long goal, unsigned long limit)
 {
 	unsigned long offset, remaining_size, areasize, preferred;
 	unsigned long i, start = 0, incr, eidx, end_pfn;
 	void *ret;

 	if (!size) {
 		printk("__alloc_bootmem_core(): zero-sized request\n");
 		BUG();
 	}
 	BUG_ON(align & (align-1));

 	if (limit && bdata->node_boot_start >= limit)
 		return NULL;

 	/* on nodes without memory - bootmem_map is NULL */
 	if (!bdata->node_bootmem_map)
 		return NULL;

 	end_pfn = bdata->node_low_pfn;
 	limit = PFN_DOWN(limit);
 	if (limit && end_pfn > limit)
 		end_pfn = limit;

 	eidx = end_pfn - PFN_DOWN(bdata->node_boot_start);
 	offset = 0;
 	if (align && (bdata->node_boot_start & (align - 1UL)) != 0)
 		offset = align - (bdata->node_boot_start & (align - 1UL));
 	offset = PFN_DOWN(offset);

 	/*
 	 * We try to allocate bootmem pages above 'goal'
 	 * first, then we try to allocate lower pages.
 	 */
 	if (goal && goal >= bdata->node_boot_start && PFN_DOWN(goal) < end_pfn) {
 		preferred = goal - bdata->node_boot_start;

 		if (bdata->last_success >= preferred)
 			if (!limit || (limit && limit > bdata->last_success))
 				preferred = bdata->last_success;
 	} else
 		preferred = 0;

 	preferred = PFN_DOWN(ALIGN(preferred, align)) + offset;
 	areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
 	incr = align >> PAGE_SHIFT ? : 1;

 restart_scan:
 	for (i = preferred; i < eidx; i += incr) {
 		unsigned long j;
 		i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
 		i = ALIGN(i, incr);
 		if (i >= eidx)
 			break;
 		if (test_bit(i, bdata->node_bootmem_map))
 			continue;
 		for (j = i + 1; j < i + areasize; ++j) {
 			if (j >= eidx)
 				goto fail_block;
 			if (test_bit(j, bdata->node_bootmem_map))
 				goto fail_block;
 		}
 		start = i;
 		goto found;
 	fail_block:
 		i = ALIGN(j, incr);
 	}

 	if (preferred > offset) {
 		preferred = offset;
 		goto restart_scan;
 	}
 	return NULL;

 found:
 	bdata->last_success = PFN_PHYS(start);
 	BUG_ON(start >= eidx);

 	/*
 	 * Is the next page of the previous allocation-end the start
 	 * of this allocation's buffer? If yes then we can 'merge'
 	 * the previous partial page with this allocation.
 	 */
 	if (align < PAGE_SIZE &&
 	    bdata->last_offset && bdata->last_pos+1 == start) {
 		offset = ALIGN(bdata->last_offset, align);
 		BUG_ON(offset > PAGE_SIZE);
 		remaining_size = PAGE_SIZE - offset;
 		if (size < remaining_size) {
 			areasize = 0;
 			/* last_pos unchanged */
 			bdata->last_offset = offset + size;
 			ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
 					   offset +
 					   bdata->node_boot_start);
 		} else {
 			remaining_size = size - remaining_size;
 			areasize = (remaining_size + PAGE_SIZE-1) / PAGE_SIZE;
 			ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
 					   offset +
 					   bdata->node_boot_start);
 			bdata->last_pos = start + areasize - 1;
 			bdata->last_offset = remaining_size;
 		}
 		bdata->last_offset &= ~PAGE_MASK;
 	} else {
 		bdata->last_pos = start + areasize - 1;
 		bdata->last_offset = size & ~PAGE_MASK;
 		ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
 	}

 	/*
 	 * Reserve the area now:
 	 */
 	for (i = start; i < start + areasize; i++)
 		if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
 			BUG();
 	memset(ret, 0, size);
 	return ret;
 }

 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
 {
 	struct page *page;
 	unsigned long pfn;
 	bootmem_data_t *bdata = pgdat->bdata;
 	unsigned long i, count, total = 0;
 	unsigned long idx;
 	unsigned long *map;
 	int gofast = 0;

 	BUG_ON(!bdata->node_bootmem_map);

 	count = 0;
 	/* first extant page of the node */
 	pfn = PFN_DOWN(bdata->node_boot_start);
 	idx = bdata->node_low_pfn - pfn;
 	map = bdata->node_bootmem_map;
 	/* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
 	if (bdata->node_boot_start == 0 ||
 	    ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
 		gofast = 1;
 	for (i = 0; i < idx; ) {
 		unsigned long v = ~map[i / BITS_PER_LONG];

 		if (gofast && v == ~0UL) {
 			int order;

 			page = pfn_to_page(pfn);
 			count += BITS_PER_LONG;
 			order = ffs(BITS_PER_LONG) - 1;
 			__free_pages_bootmem(page, order);
 			i += BITS_PER_LONG;
 			page += BITS_PER_LONG;
 		} else if (v) {
 			unsigned long m;

 			page = pfn_to_page(pfn);
 			for (m = 1; m && i < idx; m<<=1, page++, i++) {
 				if (v & m) {
 					count++;
 					__free_pages_bootmem(page, 0);
 				}
 			}
 		} else {
 			i += BITS_PER_LONG;
 		}
 		pfn += BITS_PER_LONG;
 	}
 	total += count;

 	/*
 	 * Now free the allocator bitmap itself, it's not
 	 * needed anymore:
 	 */
 	page = virt_to_page(bdata->node_bootmem_map);
 	count = 0;
 	idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
 	for (i = 0; i < idx; i++, page++) {
 		__free_pages_bootmem(page, 0);
 		count++;
 	}
 	total += count;
 	bdata->node_bootmem_map = NULL;

 	return total;
 }

 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
 				unsigned long startpfn, unsigned long endpfn)
 {
 	return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
 }

 void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 				 unsigned long size, int flags)
 {
 	reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
 }

 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
 			      unsigned long size)
 {
 	free_bootmem_core(pgdat->bdata, physaddr, size);
 }

 unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
 {
 	return free_all_bootmem_core(pgdat);
 }

 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), start, 0, pages);
 }

 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
 int __init reserve_bootmem(unsigned long addr, unsigned long size,
 			    int flags)
 {
 	return reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size, flags);
 }
 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */

 void __init free_bootmem(unsigned long addr, unsigned long size)
 {
 	free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
 }

 unsigned long __init free_all_bootmem(void)
 {
 	return free_all_bootmem_core(NODE_DATA(0));
 }

 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
 				      unsigned long goal)
 {
 	bootmem_data_t *bdata;
 	void *ptr;

 	list_for_each_entry(bdata, &bdata_list, list) {
 		ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);
 		if (ptr)
 			return ptr;
 	}
 	return NULL;
 }

 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
 			      unsigned long goal)
 {
 	void *mem = __alloc_bootmem_nopanic(size,align,goal);

 	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;
 }


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

 	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
 	if (ptr)
 		return ptr;

 	return __alloc_bootmem(size, align, goal);
 }

 #ifndef ARCH_LOW_ADDRESS_LIMIT
 #define ARCH_LOW_ADDRESS_LIMIT	0xffffffffUL
 #endif

 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
 				  unsigned long goal)
 {
 	bootmem_data_t *bdata;
 	void *ptr;

 	list_for_each_entry(bdata, &bdata_list, list) {
 		ptr = __alloc_bootmem_core(bdata, size, align, goal,
 						ARCH_LOW_ADDRESS_LIMIT);
 		if (ptr)
 			return ptr;
 	}

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

 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
 				       unsigned long align, unsigned long goal)
 {
 	return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
 				    ARCH_LOW_ADDRESS_LIMIT);
 }
	/*
	* linux/mm/bootmem.c
	*
	* Copyright (C) 1999 Ingo Molnar
	* Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
	*
	* simple boot-time physical memory area allocator and
	* free memory collector. It's used to deal with reserved
	* system memory and memory holes as well.
	*/
	#include <linux/init.h>
	#include <linux/pfn.h>
	#include <linux/bootmem.h>
	#include <linux/module.h>

	#include <asm/bug.h>
	#include <asm/io.h>
	#include <asm/processor.h>

	#include "internal.h"

	/*
	* Access to this subsystem has to be serialized externally. (this is
	* true for the boot process anyway)
	*/
	unsigned long max_low_pfn;
	unsigned long min_low_pfn;
	unsigned long max_pfn;

	static LIST_HEAD(bdata_list);
	#ifdef CONFIG_CRASH_DUMP
	/*
	* If we have booted due to a crash, max_pfn will be a very low value. We need
	* to know the amount of memory that the previous kernel used.
	*/
	unsigned long saved_max_pfn;
	#endif

	/* return the number of _pages_ that will be allocated for the boot bitmap */
	unsigned long __init bootmem_bootmap_pages(unsigned long pages)
	{
	unsigned long mapsize;

	mapsize = (pages+7)/8;
	mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
	mapsize >>= PAGE_SHIFT;

	return mapsize;
	}

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

	if (list_empty(&bdata_list)) {
	list_add(&bdata->list, &bdata_list);
	return;
	}
	/* insert in order */
	list_for_each_entry(ent, &bdata_list, list) {
	if (bdata->node_boot_start < ent->node_boot_start) {
	list_add_tail(&bdata->list, &ent->list);
	return;
	}
	}
	list_add_tail(&bdata->list, &bdata_list);
	}

	/*
	* Given an initialised bdata, it returns the size of the boot bitmap
	*/
	static unsigned long __init get_mapsize(bootmem_data_t *bdata)
	{
	unsigned long mapsize;
	unsigned long start = PFN_DOWN(bdata->node_boot_start);
	unsigned long end = bdata->node_low_pfn;

	mapsize = ((end - start) + 7) / 8;
	return ALIGN(mapsize, sizeof(long));
	}

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

	bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
	bdata->node_boot_start = PFN_PHYS(start);
	bdata->node_low_pfn = end;
	link_bootmem(bdata);

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

	return mapsize;
	}

	/*
	* Marks a particular physical memory range as unallocatable. Usable RAM
	* might be used for boot-time allocations - or it might get added
	* to the free page pool later on.
	*/
	static int __init reserve_bootmem_core(bootmem_data_t *bdata,
	unsigned long addr, unsigned long size, int flags)
	{
	unsigned long sidx, eidx;
	unsigned long i;
	int ret;

	/*
	* round up, partially reserved pages are considered
	* fully reserved.
	*/
	BUG_ON(!size);
	BUG_ON(PFN_DOWN(addr) >= bdata->node_low_pfn);
	BUG_ON(PFN_UP(addr + size) > bdata->node_low_pfn);

	sidx = PFN_DOWN(addr - bdata->node_boot_start);
	eidx = PFN_UP(addr + size - bdata->node_boot_start);

	for (i = sidx; i < eidx; i++)
	if (test_and_set_bit(i, bdata->node_bootmem_map)) {
	#ifdef CONFIG_DEBUG_BOOTMEM
	printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
	#endif
	if (flags & BOOTMEM_EXCLUSIVE) {
	ret = -EBUSY;
	goto err;
	}
	}

	return 0;

	err:
	/* unreserve memory we accidentally reserved */
	for (i--; i >= sidx; i--)
	clear_bit(i, bdata->node_bootmem_map);

	return ret;
	}

	static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
	unsigned long size)
	{
	unsigned long sidx, eidx;
	unsigned long i;

	/*
	* round down end of usable mem, partially free pages are
	* considered reserved.
	*/
	BUG_ON(!size);
	BUG_ON(PFN_DOWN(addr + size) > bdata->node_low_pfn);

	if (addr < bdata->last_success)
	bdata->last_success = addr;

	/*
	* Round up the beginning of the address.
	*/
	sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
	eidx = PFN_DOWN(addr + size - bdata->node_boot_start);

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

	/*
	* We 'merge' subsequent allocations to save space. We might 'lose'
	* some fraction of a page if allocations cannot be satisfied due to
	* size constraints on boxes where there is physical RAM space
	* fragmentation - in these cases (mostly large memory boxes) this
	* is not a problem.
	*
	* On low memory boxes we get it right in 100% of the cases.
	*
	* alignment has to be a power of 2 value.
	*
	* NOTE: This function is _not_ reentrant.
	*/
	void * __init
	__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
	unsigned long align, unsigned long goal, unsigned long limit)
	{
	unsigned long offset, remaining_size, areasize, preferred;
	unsigned long i, start = 0, incr, eidx, end_pfn;
	void *ret;

	if (!size) {
	printk("__alloc_bootmem_core(): zero-sized request\n");
	BUG();
	}
	BUG_ON(align & (align-1));

	if (limit && bdata->node_boot_start >= limit)
	return NULL;

	/* on nodes without memory - bootmem_map is NULL */
	if (!bdata->node_bootmem_map)
	return NULL;

	end_pfn = bdata->node_low_pfn;
	limit = PFN_DOWN(limit);
	if (limit && end_pfn > limit)
	end_pfn = limit;

	eidx = end_pfn - PFN_DOWN(bdata->node_boot_start);
	offset = 0;
	if (align && (bdata->node_boot_start & (align - 1UL)) != 0)
	offset = align - (bdata->node_boot_start & (align - 1UL));
	offset = PFN_DOWN(offset);

	/*
	* We try to allocate bootmem pages above 'goal'
	* first, then we try to allocate lower pages.
	*/
	if (goal && goal >= bdata->node_boot_start && PFN_DOWN(goal) < end_pfn) {
	preferred = goal - bdata->node_boot_start;

	if (bdata->last_success >= preferred)
	if (!limit \|\| (limit && limit > bdata->last_success))
	preferred = bdata->last_success;
	} else
	preferred = 0;

	preferred = PFN_DOWN(ALIGN(preferred, align)) + offset;
	areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
	incr = align >> PAGE_SHIFT ? : 1;

	restart_scan:
	for (i = preferred; i < eidx; i += incr) {
	unsigned long j;
	i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
	i = ALIGN(i, incr);
	if (i >= eidx)
	break;
	if (test_bit(i, bdata->node_bootmem_map))
	continue;
	for (j = i + 1; j < i + areasize; ++j) {
	if (j >= eidx)
	goto fail_block;
	if (test_bit(j, bdata->node_bootmem_map))
	goto fail_block;
	}
	start = i;
	goto found;
	fail_block:
	i = ALIGN(j, incr);
	}

	if (preferred > offset) {
	preferred = offset;
	goto restart_scan;
	}
	return NULL;

	found:
	bdata->last_success = PFN_PHYS(start);
	BUG_ON(start >= eidx);

	/*
	* Is the next page of the previous allocation-end the start
	* of this allocation's buffer? If yes then we can 'merge'
	* the previous partial page with this allocation.
	*/
	if (align < PAGE_SIZE &&
	bdata->last_offset && bdata->last_pos+1 == start) {
	offset = ALIGN(bdata->last_offset, align);
	BUG_ON(offset > PAGE_SIZE);
	remaining_size = PAGE_SIZE - offset;
	if (size < remaining_size) {
	areasize = 0;
	/* last_pos unchanged */
	bdata->last_offset = offset + size;
	ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
	offset +
	bdata->node_boot_start);
	} else {
	remaining_size = size - remaining_size;
	areasize = (remaining_size + PAGE_SIZE-1) / PAGE_SIZE;
	ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
	offset +
	bdata->node_boot_start);
	bdata->last_pos = start + areasize - 1;
	bdata->last_offset = remaining_size;
	}
	bdata->last_offset &= ~PAGE_MASK;
	} else {
	bdata->last_pos = start + areasize - 1;
	bdata->last_offset = size & ~PAGE_MASK;
	ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
	}

	/*
	* Reserve the area now:
	*/
	for (i = start; i < start + areasize; i++)
	if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
	BUG();
	memset(ret, 0, size);
	return ret;
	}

	static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
	{
	struct page *page;
	unsigned long pfn;
	bootmem_data_t *bdata = pgdat->bdata;
	unsigned long i, count, total = 0;
	unsigned long idx;
	unsigned long *map;
	int gofast = 0;

	BUG_ON(!bdata->node_bootmem_map);

	count = 0;
	/* first extant page of the node */
	pfn = PFN_DOWN(bdata->node_boot_start);
	idx = bdata->node_low_pfn - pfn;
	map = bdata->node_bootmem_map;
	/* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
	if (bdata->node_boot_start == 0 \|\|
	ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
	gofast = 1;
	for (i = 0; i < idx; ) {
	unsigned long v = ~map[i / BITS_PER_LONG];

	if (gofast && v == ~0UL) {
	int order;

	page = pfn_to_page(pfn);
	count += BITS_PER_LONG;
	order = ffs(BITS_PER_LONG) - 1;
	__free_pages_bootmem(page, order);
	i += BITS_PER_LONG;
	page += BITS_PER_LONG;
	} else if (v) {
	unsigned long m;

	page = pfn_to_page(pfn);
	for (m = 1; m && i < idx; m<<=1, page++, i++) {
	if (v & m) {
	count++;
	__free_pages_bootmem(page, 0);
	}
	}
	} else {
	i += BITS_PER_LONG;
	}
	pfn += BITS_PER_LONG;
	}
	total += count;

	/*
	* Now free the allocator bitmap itself, it's not
	* needed anymore:
	*/
	page = virt_to_page(bdata->node_bootmem_map);
	count = 0;
	idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
	for (i = 0; i < idx; i++, page++) {
	__free_pages_bootmem(page, 0);
	count++;
	}
	total += count;
	bdata->node_bootmem_map = NULL;

	return total;
	}

	unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
	unsigned long startpfn, unsigned long endpfn)
	{
	return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
	}

	void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
	unsigned long size, int flags)
	{
	reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
	}

	void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
	unsigned long size)
	{
	free_bootmem_core(pgdat->bdata, physaddr, size);
	}

	unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
	{
	return free_all_bootmem_core(pgdat);
	}

	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), start, 0, pages);
	}

	#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
	int __init reserve_bootmem(unsigned long addr, unsigned long size,
	int flags)
	{
	return reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size, flags);
	}
	#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */

	void __init free_bootmem(unsigned long addr, unsigned long size)
	{
	free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
	}

	unsigned long __init free_all_bootmem(void)
	{
	return free_all_bootmem_core(NODE_DATA(0));
	}

	void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
	unsigned long goal)
	{
	bootmem_data_t *bdata;
	void *ptr;

	list_for_each_entry(bdata, &bdata_list, list) {
	ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);
	if (ptr)
	return ptr;
	}
	return NULL;
	}

	void * __init __alloc_bootmem(unsigned long size, unsigned long align,
	unsigned long goal)
	{
	void *mem = __alloc_bootmem_nopanic(size,align,goal);

	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;
	}


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

	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
	if (ptr)
	return ptr;

	return __alloc_bootmem(size, align, goal);
	}

	#ifndef ARCH_LOW_ADDRESS_LIMIT
	#define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
	#endif

	void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
	unsigned long goal)
	{
	bootmem_data_t *bdata;
	void *ptr;

	list_for_each_entry(bdata, &bdata_list, list) {
	ptr = __alloc_bootmem_core(bdata, size, align, goal,
	ARCH_LOW_ADDRESS_LIMIT);
	if (ptr)
	return ptr;
	}

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

	void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
	unsigned long align, unsigned long goal)
	{
	return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
	ARCH_LOW_ADDRESS_LIMIT);
	}