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/bootmem.h>
13 #include <linux/module.h>
21 * Access to this subsystem has to be serialized externally. (this is
22 * true for the boot process anyway)
24 unsigned long max_low_pfn;
25 unsigned long min_low_pfn;
26 unsigned long max_pfn;
28 EXPORT_UNUSED_SYMBOL(max_pfn); /* June 2006 */
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;
53 static void __init link_bootmem(bootmem_data_t *bdata)
56 if (list_empty(&bdata_list)) {
57 list_add(&bdata->list, &bdata_list);
61 list_for_each_entry(ent, &bdata_list, list) {
62 if (bdata->node_boot_start < ent->node_boot_start) {
63 list_add_tail(&bdata->list, &ent->list);
67 list_add_tail(&bdata->list, &bdata_list);
73 * Called once to set up the allocator itself.
75 static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
76 unsigned long mapstart, unsigned long start, unsigned long end)
78 bootmem_data_t *bdata = pgdat->bdata;
79 unsigned long mapsize = ((end - start)+7)/8;
81 mapsize = ALIGN(mapsize, sizeof(long));
82 bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
83 bdata->node_boot_start = (start << PAGE_SHIFT);
84 bdata->node_low_pfn = end;
88 * Initially all pages are reserved - setup_arch() has to
89 * register free RAM areas explicitly.
91 memset(bdata->node_bootmem_map, 0xff, mapsize);
97 * Marks a particular physical memory range as unallocatable. Usable RAM
98 * might be used for boot-time allocations - or it might get added
99 * to the free page pool later on.
101 static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
106 * round up, partially reserved pages are considered
109 unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
110 unsigned long eidx = (addr + size - bdata->node_boot_start +
111 PAGE_SIZE-1)/PAGE_SIZE;
112 unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
115 BUG_ON(sidx >= eidx);
116 BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
117 BUG_ON(end > bdata->node_low_pfn);
119 for (i = sidx; i < eidx; i++)
120 if (test_and_set_bit(i, bdata->node_bootmem_map)) {
121 #ifdef CONFIG_DEBUG_BOOTMEM
122 printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
127 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
133 * round down end of usable mem, partially free pages are
134 * considered reserved.
137 unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
138 unsigned long end = (addr + size)/PAGE_SIZE;
141 BUG_ON(end > bdata->node_low_pfn);
143 if (addr < bdata->last_success)
144 bdata->last_success = addr;
147 * Round up the beginning of the address.
149 start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
150 sidx = start - (bdata->node_boot_start/PAGE_SIZE);
152 for (i = sidx; i < eidx; i++) {
153 if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
159 * We 'merge' subsequent allocations to save space. We might 'lose'
160 * some fraction of a page if allocations cannot be satisfied due to
161 * size constraints on boxes where there is physical RAM space
162 * fragmentation - in these cases (mostly large memory boxes) this
165 * On low memory boxes we get it right in 100% of the cases.
167 * alignment has to be a power of 2 value.
169 * NOTE: This function is _not_ reentrant.
172 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
173 unsigned long align, unsigned long goal, unsigned long limit)
175 unsigned long offset, remaining_size, areasize, preferred;
176 unsigned long i, start = 0, incr, eidx, end_pfn = bdata->node_low_pfn;
180 printk("__alloc_bootmem_core(): zero-sized request\n");
183 BUG_ON(align & (align-1));
185 if (limit && bdata->node_boot_start >= limit)
189 if (limit && end_pfn > limit)
192 eidx = end_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
195 (bdata->node_boot_start & (align - 1UL)) != 0)
196 offset = (align - (bdata->node_boot_start & (align - 1UL)));
197 offset >>= PAGE_SHIFT;
200 * We try to allocate bootmem pages above 'goal'
201 * first, then we try to allocate lower pages.
203 if (goal && (goal >= bdata->node_boot_start) &&
204 ((goal >> PAGE_SHIFT) < end_pfn)) {
205 preferred = goal - bdata->node_boot_start;
207 if (bdata->last_success >= preferred)
208 if (!limit || (limit && limit > bdata->last_success))
209 preferred = bdata->last_success;
213 preferred = ALIGN(preferred, align) >> PAGE_SHIFT;
215 areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
216 incr = align >> PAGE_SHIFT ? : 1;
219 for (i = preferred; i < eidx; i += incr) {
221 i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
225 if (test_bit(i, bdata->node_bootmem_map))
227 for (j = i + 1; j < i + areasize; ++j) {
230 if (test_bit (j, bdata->node_bootmem_map))
239 if (preferred > offset) {
246 bdata->last_success = start << PAGE_SHIFT;
247 BUG_ON(start >= eidx);
250 * Is the next page of the previous allocation-end the start
251 * of this allocation's buffer? If yes then we can 'merge'
252 * the previous partial page with this allocation.
254 if (align < PAGE_SIZE &&
255 bdata->last_offset && bdata->last_pos+1 == start) {
256 offset = ALIGN(bdata->last_offset, align);
257 BUG_ON(offset > PAGE_SIZE);
258 remaining_size = PAGE_SIZE-offset;
259 if (size < remaining_size) {
261 /* last_pos unchanged */
262 bdata->last_offset = offset+size;
263 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
264 bdata->node_boot_start);
266 remaining_size = size - remaining_size;
267 areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
268 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
269 bdata->node_boot_start);
270 bdata->last_pos = start+areasize-1;
271 bdata->last_offset = remaining_size;
273 bdata->last_offset &= ~PAGE_MASK;
275 bdata->last_pos = start + areasize - 1;
276 bdata->last_offset = size & ~PAGE_MASK;
277 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
281 * Reserve the area now:
283 for (i = start; i < start+areasize; i++)
284 if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
286 memset(ret, 0, size);
290 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
294 bootmem_data_t *bdata = pgdat->bdata;
295 unsigned long i, count, total = 0;
300 BUG_ON(!bdata->node_bootmem_map);
303 /* first extant page of the node */
304 pfn = bdata->node_boot_start >> PAGE_SHIFT;
305 idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
306 map = bdata->node_bootmem_map;
307 /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
308 if (bdata->node_boot_start == 0 ||
309 ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
311 for (i = 0; i < idx; ) {
312 unsigned long v = ~map[i / BITS_PER_LONG];
314 if (gofast && v == ~0UL) {
317 page = pfn_to_page(pfn);
318 count += BITS_PER_LONG;
319 order = ffs(BITS_PER_LONG) - 1;
320 __free_pages_bootmem(page, order);
322 page += BITS_PER_LONG;
326 page = pfn_to_page(pfn);
327 for (m = 1; m && i < idx; m<<=1, page++, i++) {
330 __free_pages_bootmem(page, 0);
336 pfn += BITS_PER_LONG;
341 * Now free the allocator bitmap itself, it's not
344 page = virt_to_page(bdata->node_bootmem_map);
346 for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
348 __free_pages_bootmem(page, 0);
351 bdata->node_bootmem_map = NULL;
356 unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn,
357 unsigned long startpfn, unsigned long endpfn)
359 return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
362 void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr,
365 reserve_bootmem_core(pgdat->bdata, physaddr, size);
368 void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr,
371 free_bootmem_core(pgdat->bdata, physaddr, size);
374 unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
376 return(free_all_bootmem_core(pgdat));
379 unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
383 return(init_bootmem_core(NODE_DATA(0), start, 0, pages));
386 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
387 void __init reserve_bootmem (unsigned long addr, unsigned long size)
389 reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
391 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
393 void __init free_bootmem (unsigned long addr, unsigned long size)
395 free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
398 unsigned long __init free_all_bootmem (void)
400 return(free_all_bootmem_core(NODE_DATA(0)));
403 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
406 bootmem_data_t *bdata;
409 list_for_each_entry(bdata, &bdata_list, list)
410 if ((ptr = __alloc_bootmem_core(bdata, size, align, goal, 0)))
415 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
418 void *mem = __alloc_bootmem_nopanic(size,align,goal);
422 * Whoops, we cannot satisfy the allocation request.
424 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
425 panic("Out of memory");
430 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
431 unsigned long align, unsigned long goal)
435 ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
439 return __alloc_bootmem(size, align, goal);
442 #define LOW32LIMIT 0xffffffff
444 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
447 bootmem_data_t *bdata;
450 list_for_each_entry(bdata, &bdata_list, list)
451 if ((ptr = __alloc_bootmem_core(bdata, size,
452 align, goal, LOW32LIMIT)))
456 * Whoops, we cannot satisfy the allocation request.
458 printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);
459 panic("Out of low memory");
463 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
464 unsigned long align, unsigned long goal)
466 return __alloc_bootmem_core(pgdat->bdata, size, align, goal, LOW32LIMIT);