bootmem.c

最新最稳定的Linux内存管理模块源代码

 * @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);
}

#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
/**
 * reserve_bootmem - mark a page range as usable
 * @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);
}
#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */

static unsigned long 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 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_core(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);
		return region;
	}

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

	return NULL;
}

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

restart:
	list_for_each_entry(bdata, &bdata_list, list) {
		void *region;

		if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
			continue;
		if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
			break;

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

	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)
{
	return ___alloc_bootmem_nopanic(size, align, goal, 0);
}

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)
{
	return ___alloc_bootmem(size, align, goal, 0);
}

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

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

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

/**
 * __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)
{
	return ___alloc_bootmem_node(pgdat->bdata, size, align, goal, 0);
}

#ifdef CONFIG_SPARSEMEM
/**
 * alloc_bootmem_section - allocate boot memory from a specific section
 * @size: size of the request in bytes
 * @section_nr: sparse map section to allocate from
 *
 * Return NULL on failure.
 */
void * __init alloc_bootmem_section(unsigned long size,
				    unsigned long section_nr)
{
	bootmem_data_t *bdata;
	unsigned long pfn, goal, limit;

	pfn = section_nr_to_pfn(section_nr);
	goal = pfn << PAGE_SHIFT;
	limit = section_nr_to_pfn(section_nr + 1) << PAGE_SHIFT;
	bdata = &bootmem_node_data[early_pfn_to_nid(pfn)];

	return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, limit);
}
#endif

void * __init __alloc_bootmem_node_nopanic(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_nopanic(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);
}

/**
 * __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)
{
	return ___alloc_bootmem_node(pgdat->bdata, size, align,
				goal, ARCH_LOW_ADDRESS_LIMIT);
}