linux-stable/mm/bootmem.c
David Howells a226f6c899 [PATCH] FRV: Clean up bootmem allocator's page freeing algorithm
The attached patch cleans up the way the bootmem allocator frees pages.

A new function, __free_pages_bootmem(), is provided in mm/page_alloc.c that is
called from mm/bootmem.c to turn pages over to the main allocator.  All the
bits of code to initialise pages (clearing PG_reserved and setting the page
count) are moved to here.  The checks on page validity are removed, on the
assumption that the struct page arrays will have been prepared correctly.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:26 -08:00

439 lines
11 KiB
C

/*
* 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/mm.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <asm/dma.h>
#include <asm/io.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;
EXPORT_SYMBOL(max_pfn); /* This is exported so
* dma_get_required_mask(), which uses
* it, can be an inline function */
#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;
}
/*
* 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 = ((end - start)+7)/8;
pgdat->pgdat_next = pgdat_list;
pgdat_list = pgdat;
mapsize = ALIGN(mapsize, sizeof(long));
bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
bdata->node_boot_start = (start << PAGE_SHIFT);
bdata->node_low_pfn = end;
/*
* Initially all pages are reserved - setup_arch() has to
* register free RAM areas explicitly.
*/
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 void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
{
unsigned long i;
/*
* round up, partially reserved pages are considered
* fully reserved.
*/
unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
unsigned long eidx = (addr + size - bdata->node_boot_start +
PAGE_SIZE-1)/PAGE_SIZE;
unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
BUG_ON(!size);
BUG_ON(sidx >= eidx);
BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
BUG_ON(end > bdata->node_low_pfn);
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
}
}
static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
{
unsigned long i;
unsigned long start;
/*
* round down end of usable mem, partially free pages are
* considered reserved.
*/
unsigned long sidx;
unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
unsigned long end = (addr + size)/PAGE_SIZE;
BUG_ON(!size);
BUG_ON(end > bdata->node_low_pfn);
if (addr < bdata->last_success)
bdata->last_success = addr;
/*
* Round up the beginning of the address.
*/
start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
sidx = start - (bdata->node_boot_start/PAGE_SIZE);
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.
*/
static 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 = bdata->node_low_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;
limit >>=PAGE_SHIFT;
if (limit && end_pfn > limit)
end_pfn = limit;
eidx = end_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
offset = 0;
if (align &&
(bdata->node_boot_start & (align - 1UL)) != 0)
offset = (align - (bdata->node_boot_start & (align - 1UL)));
offset >>= PAGE_SHIFT;
/*
* We try to allocate bootmem pages above 'goal'
* first, then we try to allocate lower pages.
*/
if (goal && (goal >= bdata->node_boot_start) &&
((goal >> PAGE_SHIFT) < 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 = ALIGN(preferred, align) >> PAGE_SHIFT;
preferred += 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 = start << PAGE_SHIFT;
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 = bdata->node_boot_start >> PAGE_SHIFT;
idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
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;
for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
count++;
__free_pages_bootmem(page, 0);
}
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)
{
reserve_bootmem_core(pgdat->bdata, physaddr, size);
}
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
void __init reserve_bootmem (unsigned long addr, unsigned long size)
{
reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
}
#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(unsigned long size, unsigned long align, unsigned long goal)
{
pg_data_t *pgdat = pgdat_list;
void *ptr;
for_each_pgdat(pgdat)
if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
align, goal, 0)))
return(ptr);
/*
* 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);
}
#define LOW32LIMIT 0xffffffff
void * __init __alloc_bootmem_low(unsigned long size, unsigned long align, unsigned long goal)
{
pg_data_t *pgdat = pgdat_list;
void *ptr;
for_each_pgdat(pgdat)
if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
align, goal, LOW32LIMIT)))
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, LOW32LIMIT);
}