/*
* linux/mm/initmem.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/swapctl.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mmzone.h>
#include <asm/dma.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;
/* return the number of _pages_ that will be allocated for the boot bitmap */
30 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;
38 return mapsize;
}
/*
* Called once to set up the allocator itself.
*/
44 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->node_next = pgdat_list;
pgdat_list = pgdat;
mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
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);
64 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.
*/
72 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;
84 if (!size) BUG();
86 if (end > bdata->node_low_pfn)
87 BUG();
88 for (i = sidx; i < eidx; i++)
89 if (test_and_set_bit(i, bdata->node_bootmem_map))
printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
}
93 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;
105 if (!size) BUG();
106 if (end > bdata->node_low_pfn)
107 BUG();
/*
* Round up the beginning of the address.
*/
start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
sidx = start - (bdata->node_boot_start/PAGE_SIZE);
115 for (i = sidx; i < eidx; i++) {
116 if (!test_and_clear_bit(i, bdata->node_bootmem_map))
117 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.
*/
134 static void * __init __alloc_bootmem_core (bootmem_data_t *bdata,
unsigned long size, unsigned long align, unsigned long goal)
{
unsigned long i, start = 0;
void *ret;
unsigned long offset, remaining_size;
unsigned long areasize, preferred, incr;
unsigned long eidx = bdata->node_low_pfn - (bdata->node_boot_start >>
PAGE_SHIFT);
144 if (!size) BUG();
/*
* We try to allocate bootmem pages above 'goal'
* first, then we try to allocate lower pages.
*/
if (goal && (goal >= bdata->node_boot_start) &&
151 ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
preferred = goal - bdata->node_boot_start;
153 } else
preferred = 0;
preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
incr = align >> PAGE_SHIFT ? : 1;
restart_scan:
161 for (i = preferred; i < eidx; i += incr) {
unsigned long j;
163 if (test_bit(i, bdata->node_bootmem_map))
164 continue;
165 for (j = i + 1; j < i + areasize; ++j) {
166 if (j >= eidx)
167 goto fail_block;
168 if (test_bit (j, bdata->node_bootmem_map))
169 goto fail_block;
}
start = i;
172 goto found;
fail_block:;
}
175 if (preferred) {
preferred = 0;
177 goto restart_scan;
}
found:
180 if (start >= eidx)
181 BUG();
/*
* 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
189 && bdata->last_offset && bdata->last_pos+1 == start) {
offset = (bdata->last_offset+align-1) & ~(align-1);
191 if (offset > PAGE_SIZE)
192 BUG();
remaining_size = PAGE_SIZE-offset;
194 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);
200 } 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;
209 } 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:
*/
217 for (i = start; i < start+areasize; i++)
218 if (test_and_set_bit(i, bdata->node_bootmem_map))
219 BUG();
memset(ret, 0, size);
221 return ret;
}
224 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
{
struct page *page = pgdat->node_mem_map;
bootmem_data_t *bdata = pgdat->bdata;
unsigned long i, count, total = 0;
unsigned long idx;
231 if (!bdata->node_bootmem_map) BUG();
count = 0;
idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
235 for (i = 0; i < idx; i++, page++) {
236 if (!test_bit(i, bdata->node_bootmem_map)) {
count++;
ClearPageReserved(page);
set_page_count(page, 1);
__free_page(page);
}
}
total += count;
/*
* Now free the allocator bitmap itself, it's not
* needed anymore:
*/
page = virt_to_page(bdata->node_bootmem_map);
count = 0;
251 for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
count++;
ClearPageReserved(page);
set_page_count(page, 1);
__free_page(page);
}
total += count;
bdata->node_bootmem_map = NULL;
260 return total;
}
263 unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
{
265 return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
}
268 void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
{
reserve_bootmem_core(pgdat->bdata, physaddr, size);
}
273 void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
{
275 return(free_bootmem_core(pgdat->bdata, physaddr, size));
}
278 unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
{
280 return(free_all_bootmem_core(pgdat));
}
283 unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
{
max_low_pfn = pages;
min_low_pfn = start;
287 return(init_bootmem_core(&contig_page_data, start, 0, pages));
}
290 void __init reserve_bootmem (unsigned long addr, unsigned long size)
{
reserve_bootmem_core(contig_page_data.bdata, addr, size);
}
295 void __init free_bootmem (unsigned long addr, unsigned long size)
{
297 return(free_bootmem_core(contig_page_data.bdata, addr, size));
}
300 unsigned long __init free_all_bootmem (void)
{
302 return(free_all_bootmem_core(&contig_page_data));
}
305 void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
{
pg_data_t *pgdat = pgdat_list;
void *ptr;
310 while (pgdat) {
if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
312 align, goal)))
313 return(ptr);
pgdat = pgdat->node_next;
}
/*
* Whoops, we cannot satisfy the allocation request.
*/
319 BUG();
320 return NULL;
}
323 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);
328 if (ptr)
329 return (ptr);
/*
* Whoops, we cannot satisfy the allocation request.
*/
334 BUG();
335 return NULL;
}