4 * Copyright (C) 1999 Ingo Molnar
5 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
7 * simple boot-time physical memory area allocator and
8 * free memory collector. It's used to deal with reserved
9 * system memory and memory holes as well.
11 #include <linux/init.h>
12 #include <linux/pfn.h>
13 #include <linux/bootmem.h>
14 #include <linux/module.h>
18 #include <asm/processor.h>
23 * Access to this subsystem has to be serialized externally. (this is
24 * true for the boot process anyway)
26 unsigned long max_low_pfn;
27 unsigned long min_low_pfn;
28 unsigned long max_pfn;
30 static LIST_HEAD(bdata_list);
31 #ifdef CONFIG_CRASH_DUMP
33 * If we have booted due to a crash, max_pfn will be a very low value. We need
34 * to know the amount of memory that the previous kernel used.
36 unsigned long saved_max_pfn;
39 /* return the number of _pages_ that will be allocated for the boot bitmap */
40 unsigned long __init bootmem_bootmap_pages(unsigned long pages)
42 unsigned long mapsize;
44 mapsize = (pages+7)/8;
45 mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
46 mapsize >>= PAGE_SHIFT;
54 static void __init link_bootmem(bootmem_data_t *bdata)
58 if (list_empty(&bdata_list)) {
59 list_add(&bdata->list, &bdata_list);
63 list_for_each_entry(ent, &bdata_list, list) {
64 if (bdata->node_boot_start < ent->node_boot_start) {
65 list_add_tail(&bdata->list, &ent->list);
69 list_add_tail(&bdata->list, &bdata_list);
73 * Given an initialised bdata, it returns the size of the boot bitmap
75 static unsigned long __init get_mapsize(bootmem_data_t *bdata)
77 unsigned long mapsize;
78 unsigned long start = PFN_DOWN(bdata->node_boot_start);
79 unsigned long end = bdata->node_low_pfn;
81 mapsize = ((end - start) + 7) / 8;
82 return ALIGN(mapsize, sizeof(long));
86 * Called once to set up the allocator itself.
88 static unsigned long __init init_bootmem_core(pg_data_t *pgdat,
89 unsigned long mapstart, unsigned long start, unsigned long end)
91 bootmem_data_t *bdata = pgdat->bdata;
92 unsigned long mapsize;
94 bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
95 bdata->node_boot_start = PFN_PHYS(start);
96 bdata->node_low_pfn = end;
100 * Initially all pages are reserved - setup_arch() has to
101 * register free RAM areas explicitly.
103 mapsize = get_mapsize(bdata);
104 memset(bdata->node_bootmem_map, 0xff, mapsize);
110 * Marks a particular physical memory range as unallocatable. Usable RAM
111 * might be used for boot-time allocations - or it might get added
112 * to the free page pool later on.
114 static int __init reserve_bootmem_core(bootmem_data_t *bdata,
115 unsigned long addr, unsigned long size, int flags)
117 unsigned long sidx, eidx;
122 * round up, partially reserved pages are considered
126 BUG_ON(PFN_DOWN(addr) >= bdata->node_low_pfn);
127 BUG_ON(PFN_UP(addr + size) > bdata->node_low_pfn);
128 BUG_ON(addr < bdata->node_boot_start);
130 sidx = PFN_DOWN(addr - bdata->node_boot_start);
131 eidx = PFN_UP(addr + size - bdata->node_boot_start);
133 for (i = sidx; i < eidx; i++)
134 if (test_and_set_bit(i, bdata->node_bootmem_map)) {
135 #ifdef CONFIG_DEBUG_BOOTMEM
136 printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
138 if (flags & BOOTMEM_EXCLUSIVE) {
147 /* unreserve memory we accidentally reserved */
148 for (i--; i >= sidx; i--)
149 clear_bit(i, bdata->node_bootmem_map);
154 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
157 unsigned long sidx, eidx;
163 if (addr + size < bdata->node_boot_start ||
164 PFN_DOWN(addr) > bdata->node_low_pfn)
167 * round down end of usable mem, partially free pages are
168 * considered reserved.
171 if (addr >= bdata->node_boot_start && addr < bdata->last_success)
172 bdata->last_success = addr;
175 * Round up to index to the range.
177 if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
178 sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
182 eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
183 if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
184 eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
186 for (i = sidx; i < eidx; i++) {
187 if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
193 * We 'merge' subsequent allocations to save space. We might 'lose'
194 * some fraction of a page if allocations cannot be satisfied due to
195 * size constraints on boxes where there is physical RAM space
196 * fragmentation - in these cases (mostly large memory boxes) this
199 * On low memory boxes we get it right in 100% of the cases.
201 * alignment has to be a power of 2 value.
203 * NOTE: This function is _not_ reentrant.
206 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
207 unsigned long align, unsigned long goal, unsigned long limit)
209 unsigned long offset, remaining_size, areasize, preferred;
210 unsigned long i, start = 0, incr, eidx, end_pfn;
214 printk("__alloc_bootmem_core(): zero-sized request\n");
217 BUG_ON(align & (align-1));
219 if (limit && bdata->node_boot_start >= limit)
222 /* on nodes without memory - bootmem_map is NULL */
223 if (!bdata->node_bootmem_map)
226 end_pfn = bdata->node_low_pfn;
227 limit = PFN_DOWN(limit);
228 if (limit && end_pfn > limit)
231 eidx = end_pfn - PFN_DOWN(bdata->node_boot_start);
233 if (align && (bdata->node_boot_start & (align - 1UL)) != 0)
234 offset = align - (bdata->node_boot_start & (align - 1UL));
235 offset = PFN_DOWN(offset);
238 * We try to allocate bootmem pages above 'goal'
239 * first, then we try to allocate lower pages.
242 if (goal && PFN_DOWN(goal) < end_pfn) {
243 if (goal > bdata->node_boot_start)
244 preferred = goal - bdata->node_boot_start;
246 if (bdata->last_success >= preferred)
247 if (!limit || (limit && limit > bdata->last_success))
248 preferred = bdata->last_success;
251 preferred = PFN_DOWN(ALIGN(preferred, align)) + offset;
252 areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
253 incr = align >> PAGE_SHIFT ? : 1;
256 for (i = preferred; i < eidx;) {
259 i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
263 if (test_bit(i, bdata->node_bootmem_map)) {
267 for (j = i + 1; j < i + areasize; ++j) {
270 if (test_bit(j, bdata->node_bootmem_map))
281 if (preferred > offset) {
288 bdata->last_success = PFN_PHYS(start);
289 BUG_ON(start >= eidx);
292 * Is the next page of the previous allocation-end the start
293 * of this allocation's buffer? If yes then we can 'merge'
294 * the previous partial page with this allocation.
296 if (align < PAGE_SIZE &&
297 bdata->last_offset && bdata->last_pos+1 == start) {
298 offset = ALIGN(bdata->last_offset, align);
299 BUG_ON(offset > PAGE_SIZE);
300 remaining_size = PAGE_SIZE - offset;
301 if (size < remaining_size) {
303 /* last_pos unchanged */
304 bdata->last_offset = offset + size;
305 ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
307 bdata->node_boot_start);
309 remaining_size = size - remaining_size;
310 areasize = (remaining_size + PAGE_SIZE-1) / PAGE_SIZE;
311 ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
313 bdata->node_boot_start);
314 bdata->last_pos = start + areasize - 1;
315 bdata->last_offset = remaining_size;
317 bdata->last_offset &= ~PAGE_MASK;
319 bdata->last_pos = start + areasize - 1;
320 bdata->last_offset = size & ~PAGE_MASK;
321 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
325 * Reserve the area now:
327 for (i = start; i < start + areasize; i++)
328 if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
330 memset(ret, 0, size);
334 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
338 bootmem_data_t *bdata = pgdat->bdata;
339 unsigned long i, count, total = 0;
344 BUG_ON(!bdata->node_bootmem_map);
347 /* first extant page of the node */
348 pfn = PFN_DOWN(bdata->node_boot_start);
349 idx = bdata->node_low_pfn - pfn;
350 map = bdata->node_bootmem_map;
351 /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
352 if (bdata->node_boot_start == 0 ||
353 ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
355 for (i = 0; i < idx; ) {
356 unsigned long v = ~map[i / BITS_PER_LONG];
358 if (gofast && v == ~0UL) {
361 page = pfn_to_page(pfn);
362 count += BITS_PER_LONG;
363 order = ffs(BITS_PER_LONG) - 1;
364 __free_pages_bootmem(page, order);
366 page += BITS_PER_LONG;
370 page = pfn_to_page(pfn);
371 for (m = 1; m && i < idx; m<<=1, page++, i++) {
374 __free_pages_bootmem(page, 0);
380 pfn += BITS_PER_LONG;
385 * Now free the allocator bitmap itself, it's not
388 page = virt_to_page(bdata->node_bootmem_map);
390 idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
391 for (i = 0; i < idx; i++, page++) {
392 __free_pages_bootmem(page, 0);
396 bdata->node_bootmem_map = NULL;
401 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
402 unsigned long startpfn, unsigned long endpfn)
404 return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
407 void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
408 unsigned long size, int flags)
410 reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
413 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
416 free_bootmem_core(pgdat->bdata, physaddr, size);
419 unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
421 return free_all_bootmem_core(pgdat);
424 unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
428 return init_bootmem_core(NODE_DATA(0), start, 0, pages);
431 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
432 int __init reserve_bootmem(unsigned long addr, unsigned long size,
435 return reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size, flags);
437 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
439 void __init free_bootmem(unsigned long addr, unsigned long size)
441 bootmem_data_t *bdata;
442 list_for_each_entry(bdata, &bdata_list, list)
443 free_bootmem_core(bdata, addr, size);
446 unsigned long __init free_all_bootmem(void)
448 return free_all_bootmem_core(NODE_DATA(0));
451 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
454 bootmem_data_t *bdata;
457 list_for_each_entry(bdata, &bdata_list, list) {
458 ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);
465 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
468 void *mem = __alloc_bootmem_nopanic(size,align,goal);
473 * Whoops, we cannot satisfy the allocation request.
475 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
476 panic("Out of memory");
481 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
482 unsigned long align, unsigned long goal)
486 ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
490 return __alloc_bootmem(size, align, goal);
493 #ifndef ARCH_LOW_ADDRESS_LIMIT
494 #define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
497 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
500 bootmem_data_t *bdata;
503 list_for_each_entry(bdata, &bdata_list, list) {
504 ptr = __alloc_bootmem_core(bdata, size, align, goal,
505 ARCH_LOW_ADDRESS_LIMIT);
511 * Whoops, we cannot satisfy the allocation request.
513 printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);
514 panic("Out of low memory");
518 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
519 unsigned long align, unsigned long goal)
521 return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
522 ARCH_LOW_ADDRESS_LIMIT);