linux/mm/bootmem.c

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/*
* 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/bootmem.h>
#include <linux/module.h>
#include <asm/bug.h>
#include <asm/io.h>
#include <asm/processor.h>
#include "internal.h"
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
bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
/*
* 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));
}
/**
* 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 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);
}
/*
* 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_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;
}
/**
* 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);
}
static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
{
struct page *page;
unsigned long pfn;
unsigned long i, count;
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 if we are aligned to BITS_PER_LONG pages. If so, we might
* be able to free page orders of that size at once.
*/
if (!(pfn & (BITS_PER_LONG-1)))
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;
}
/*
* Now free the allocator bitmap itself, it's not
* needed anymore:
*/
page = virt_to_page(bdata->node_bootmem_map);
idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
for (i = 0; i < idx; i++, page++)
__free_pages_bootmem(page, 0);
count += i;
bdata->node_bootmem_map = NULL;
return count;
}
/**
* free_all_bootmem_node - release a node's free pages to the buddy allocator
* @pgdat: node to be released
*
* Returns the number of pages actually released.
*/
unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
{
register_page_bootmem_info_node(pgdat);
return free_all_bootmem_core(pgdat->bdata);
}
/**
* free_all_bootmem - release free pages to the buddy allocator
*
* Returns the number of pages actually released.
*/
unsigned long __init free_all_bootmem(void)
{
return free_all_bootmem_core(NODE_DATA(0)->bdata);
}
static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
unsigned long size)
{
unsigned long sidx, eidx;
unsigned long i;
BUG_ON(!size);
/* out range */
if (addr + size < bdata->node_boot_start ||
PFN_DOWN(addr) > bdata->node_low_pfn)
return;
/*
* round down end of usable mem, partially free pages are
* considered reserved.
*/
if (addr >= bdata->node_boot_start && addr < bdata->last_success)
bdata->last_success = addr;
/*
* Round up to index to the range.
*/
if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
else
sidx = 0;
eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
for (i = sidx; i < eidx; i++) {
if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
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.
*
* Only physical pages that actually reside on @pgdat are marked.
*/
void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
unsigned long size)
{
free_bootmem_core(pgdat->bdata, physaddr, size);
}
/**
* free_bootmem - mark a page range as usable
* @addr: starting address of the range
* @size: size of the range in bytes
*
* Partial pages will be considered reserved and left as they are.
*
* All physical pages within the range are marked, no matter what
* node they reside on.
*/
void __init free_bootmem(unsigned long addr, unsigned long size)
{
bootmem_data_t *bdata;
list_for_each_entry(bdata, &bdata_list, list)
free_bootmem_core(bdata, addr, size);
}
/*
* 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 can_reserve_bootmem_core(bootmem_data_t *bdata,
unsigned long addr, unsigned long size, int flags)
{
unsigned long sidx, eidx;
unsigned long i;
BUG_ON(!size);
/* out of range, don't hold other */
if (addr + size < bdata->node_boot_start ||
PFN_DOWN(addr) > bdata->node_low_pfn)
return 0;
/*
* Round up to index to the range.
*/
if (addr > bdata->node_boot_start)
sidx= PFN_DOWN(addr - bdata->node_boot_start);
else
sidx = 0;
eidx = PFN_UP(addr + size - bdata->node_boot_start);
if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
for (i = sidx; i < eidx; i++) {
if (test_bit(i, bdata->node_bootmem_map)) {
if (flags & BOOTMEM_EXCLUSIVE)
return -EBUSY;
}
}
return 0;
}
static void __init reserve_bootmem_core(bootmem_data_t *bdata,
unsigned long addr, unsigned long size, int flags)
{
unsigned long sidx, eidx;
unsigned long i;
BUG_ON(!size);
/* out of range */
if (addr + size < bdata->node_boot_start ||
PFN_DOWN(addr) > bdata->node_low_pfn)
return;
/*
* Round up to index to the range.
*/
if (addr > bdata->node_boot_start)
sidx= PFN_DOWN(addr - bdata->node_boot_start);
else
sidx = 0;
eidx = PFN_UP(addr + size - bdata->node_boot_start);
if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
eidx = bdata->node_low_pfn - PFN_DOWN(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
}
}
}
/**
* 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.
*
* Only physical pages that actually reside on @pgdat are marked.
*/
int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
unsigned long size, int flags)
{
int ret;
ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
if (ret < 0)
return -ENOMEM;
reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
return 0;
}
#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.
*
* All physical pages within the range are marked, no matter what
* node they reside on.
*/
int __init reserve_bootmem(unsigned long addr, unsigned long size,
int flags)
{
bootmem_data_t *bdata;
int ret;
list_for_each_entry(bdata, &bdata_list, list) {
ret = can_reserve_bootmem_core(bdata, addr, size, flags);
if (ret < 0)
return ret;
}
list_for_each_entry(bdata, &bdata_list, list)
reserve_bootmem_core(bdata, addr, size, flags);
return 0;
}
#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
/*
* 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.
*/
static void * __init
alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
unsigned long align, unsigned long goal, unsigned long limit)
{
unsigned long areasize, preferred;
unsigned long i, start = 0, incr, eidx, end_pfn;
void *ret;
unsigned long node_boot_start;
void *node_bootmem_map;
if (!size) {
printk("alloc_bootmem_core(): zero-sized request\n");
BUG();
}
BUG_ON(align & (align-1));
/* on nodes without memory - bootmem_map is NULL */
if (!bdata->node_bootmem_map)
return NULL;
/* bdata->node_boot_start is supposed to be (12+6)bits alignment on x86_64 ? */
node_boot_start = bdata->node_boot_start;
node_bootmem_map = bdata->node_bootmem_map;
if (align) {
node_boot_start = ALIGN(bdata->node_boot_start, align);
if (node_boot_start > bdata->node_boot_start)
node_bootmem_map = (unsigned long *)bdata->node_bootmem_map +
PFN_DOWN(node_boot_start - bdata->node_boot_start)/BITS_PER_LONG;
}
if (limit && node_boot_start >= limit)
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(node_boot_start);
/*
* We try to allocate bootmem pages above 'goal'
* first, then we try to allocate lower pages.
*/
preferred = 0;
if (goal && PFN_DOWN(goal) < end_pfn) {
if (goal > node_boot_start)
preferred = goal - node_boot_start;
if (bdata->last_success > node_boot_start &&
bdata->last_success - node_boot_start >= preferred)
if (!limit || (limit && limit > bdata->last_success))
preferred = bdata->last_success - node_boot_start;
}
preferred = PFN_DOWN(ALIGN(preferred, align));
areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
incr = align >> PAGE_SHIFT ? : 1;
restart_scan:
for (i = preferred; i < eidx;) {
unsigned long j;
i = find_next_zero_bit(node_bootmem_map, eidx, i);
i = ALIGN(i, incr);
if (i >= eidx)
break;
if (test_bit(i, node_bootmem_map)) {
i += incr;
continue;
}
for (j = i + 1; j < i + areasize; ++j) {
if (j >= eidx)
goto fail_block;
if (test_bit(j, node_bootmem_map))
goto fail_block;
}
start = i;
goto found;
fail_block:
i = ALIGN(j, incr);
if (i == j)
i += incr;
}
if (preferred > 0) {
preferred = 0;
goto restart_scan;
}
return NULL;
found:
bdata->last_success = PFN_PHYS(start) + node_boot_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) {
unsigned long offset, remaining_size;
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 + 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 + 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 + node_boot_start);
}
/*
* Reserve the area now:
*/
for (i = start; i < start + areasize; i++)
if (unlikely(test_and_set_bit(i, node_bootmem_map)))
BUG();
memset(ret, 0, size);
return ret;
}
/**
* __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)
{
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;
}
/**
* __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)
{
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;
}
/**
* __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)
{
void *ptr;
ptr = alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
if (ptr)
return ptr;
return __alloc_bootmem(size, align, goal);
}
#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)
{
void *ptr;
unsigned long limit, goal, start_nr, end_nr, pfn;
struct pglist_data *pgdat;
pfn = section_nr_to_pfn(section_nr);
goal = PFN_PHYS(pfn);
limit = PFN_PHYS(section_nr_to_pfn(section_nr + 1)) - 1;
pgdat = NODE_DATA(early_pfn_to_nid(pfn));
ptr = alloc_bootmem_core(pgdat->bdata, size, SMP_CACHE_BYTES, goal,
limit);
if (!ptr)
return NULL;
start_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr)));
end_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr) + size));
if (start_nr != section_nr || end_nr != section_nr) {
printk(KERN_WARNING "alloc_bootmem failed on section %ld.\n",
section_nr);
free_bootmem_core(pgdat->bdata, __pa(ptr), size);
ptr = NULL;
}
return ptr;
}
#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)
{
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;
}
/**
* __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_core(pgdat->bdata, size, align, goal,
ARCH_LOW_ADDRESS_LIMIT);
}