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 areasize, preferred;
210 unsigned long i, start = 0, incr, eidx, end_pfn;
212 unsigned long node_boot_start;
213 void *node_bootmem_map;
216 printk("__alloc_bootmem_core(): zero-sized request\n");
219 BUG_ON(align & (align-1));
221 /* on nodes without memory - bootmem_map is NULL */
222 if (!bdata->node_bootmem_map)
225 /* bdata->node_boot_start is supposed to be (12+6)bits alignment on x86_64 ? */
226 node_boot_start = bdata->node_boot_start;
227 node_bootmem_map = bdata->node_bootmem_map;
229 node_boot_start = ALIGN(bdata->node_boot_start, align);
230 if (node_boot_start > bdata->node_boot_start)
231 node_bootmem_map = (unsigned long *)bdata->node_bootmem_map +
232 PFN_DOWN(node_boot_start - bdata->node_boot_start)/BITS_PER_LONG;
235 if (limit && node_boot_start >= limit)
238 end_pfn = bdata->node_low_pfn;
239 limit = PFN_DOWN(limit);
240 if (limit && end_pfn > limit)
243 eidx = end_pfn - PFN_DOWN(node_boot_start);
246 * We try to allocate bootmem pages above 'goal'
247 * first, then we try to allocate lower pages.
250 if (goal && PFN_DOWN(goal) < end_pfn) {
251 if (goal > node_boot_start)
252 preferred = goal - node_boot_start;
254 if (bdata->last_success > node_boot_start &&
255 bdata->last_success - node_boot_start >= preferred)
256 if (!limit || (limit && limit > bdata->last_success))
257 preferred = bdata->last_success - node_boot_start;
260 preferred = PFN_DOWN(ALIGN(preferred, align));
261 areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
262 incr = align >> PAGE_SHIFT ? : 1;
265 for (i = preferred; i < eidx;) {
268 i = find_next_zero_bit(node_bootmem_map, eidx, i);
272 if (test_bit(i, node_bootmem_map)) {
276 for (j = i + 1; j < i + areasize; ++j) {
279 if (test_bit(j, node_bootmem_map))
297 bdata->last_success = PFN_PHYS(start) + node_boot_start;
298 BUG_ON(start >= eidx);
301 * Is the next page of the previous allocation-end the start
302 * of this allocation's buffer? If yes then we can 'merge'
303 * the previous partial page with this allocation.
305 if (align < PAGE_SIZE &&
306 bdata->last_offset && bdata->last_pos+1 == start) {
307 unsigned long offset, remaining_size;
308 offset = ALIGN(bdata->last_offset, align);
309 BUG_ON(offset > PAGE_SIZE);
310 remaining_size = PAGE_SIZE - offset;
311 if (size < remaining_size) {
313 /* last_pos unchanged */
314 bdata->last_offset = offset + size;
315 ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
316 offset + node_boot_start);
318 remaining_size = size - remaining_size;
319 areasize = (remaining_size + PAGE_SIZE-1) / PAGE_SIZE;
320 ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
321 offset + node_boot_start);
322 bdata->last_pos = start + areasize - 1;
323 bdata->last_offset = remaining_size;
325 bdata->last_offset &= ~PAGE_MASK;
327 bdata->last_pos = start + areasize - 1;
328 bdata->last_offset = size & ~PAGE_MASK;
329 ret = phys_to_virt(start * PAGE_SIZE + node_boot_start);
333 * Reserve the area now:
335 for (i = start; i < start + areasize; i++)
336 if (unlikely(test_and_set_bit(i, node_bootmem_map)))
338 memset(ret, 0, size);
342 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
346 bootmem_data_t *bdata = pgdat->bdata;
347 unsigned long i, count, total = 0;
352 BUG_ON(!bdata->node_bootmem_map);
355 /* first extant page of the node */
356 pfn = PFN_DOWN(bdata->node_boot_start);
357 idx = bdata->node_low_pfn - pfn;
358 map = bdata->node_bootmem_map;
359 /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
360 if (bdata->node_boot_start == 0 ||
361 ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
363 for (i = 0; i < idx; ) {
364 unsigned long v = ~map[i / BITS_PER_LONG];
366 if (gofast && v == ~0UL) {
369 page = pfn_to_page(pfn);
370 count += BITS_PER_LONG;
371 order = ffs(BITS_PER_LONG) - 1;
372 __free_pages_bootmem(page, order);
374 page += BITS_PER_LONG;
378 page = pfn_to_page(pfn);
379 for (m = 1; m && i < idx; m<<=1, page++, i++) {
382 __free_pages_bootmem(page, 0);
388 pfn += BITS_PER_LONG;
393 * Now free the allocator bitmap itself, it's not
396 page = virt_to_page(bdata->node_bootmem_map);
398 idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
399 for (i = 0; i < idx; i++, page++) {
400 __free_pages_bootmem(page, 0);
404 bdata->node_bootmem_map = NULL;
409 unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
410 unsigned long startpfn, unsigned long endpfn)
412 return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
415 void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
416 unsigned long size, int flags)
418 reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
421 void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
424 free_bootmem_core(pgdat->bdata, physaddr, size);
427 unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
429 return free_all_bootmem_core(pgdat);
432 unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
436 return init_bootmem_core(NODE_DATA(0), start, 0, pages);
439 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
440 int __init reserve_bootmem(unsigned long addr, unsigned long size,
443 return reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size, flags);
445 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
447 void __init free_bootmem(unsigned long addr, unsigned long size)
449 bootmem_data_t *bdata;
450 list_for_each_entry(bdata, &bdata_list, list)
451 free_bootmem_core(bdata, addr, size);
454 unsigned long __init free_all_bootmem(void)
456 return free_all_bootmem_core(NODE_DATA(0));
459 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
462 bootmem_data_t *bdata;
465 list_for_each_entry(bdata, &bdata_list, list) {
466 ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);
473 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
476 void *mem = __alloc_bootmem_nopanic(size,align,goal);
481 * Whoops, we cannot satisfy the allocation request.
483 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
484 panic("Out of memory");
489 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
490 unsigned long align, unsigned long goal)
494 ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
498 return __alloc_bootmem(size, align, goal);
501 #ifndef ARCH_LOW_ADDRESS_LIMIT
502 #define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
505 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
508 bootmem_data_t *bdata;
511 list_for_each_entry(bdata, &bdata_list, list) {
512 ptr = __alloc_bootmem_core(bdata, size, align, goal,
513 ARCH_LOW_ADDRESS_LIMIT);
519 * Whoops, we cannot satisfy the allocation request.
521 printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);
522 panic("Out of low memory");
526 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
527 unsigned long align, unsigned long goal)
529 return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
530 ARCH_LOW_ADDRESS_LIMIT);