bootmem.c 12.1 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
11
/*
 *  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/init.h>
12
#include <linux/pfn.h>
Linus Torvalds's avatar
Linus Torvalds committed
13
14
#include <linux/bootmem.h>
#include <linux/module.h>
15
16

#include <asm/bug.h>
Linus Torvalds's avatar
Linus Torvalds committed
17
#include <asm/io.h>
18
#include <asm/processor.h>
19

Linus Torvalds's avatar
Linus Torvalds committed
20
21
22
23
24
25
26
27
28
29
#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;

30
EXPORT_UNUSED_SYMBOL(max_pfn);  /*  June 2006  */
Linus Torvalds's avatar
Linus Torvalds committed
31

32
static LIST_HEAD(bdata_list);
33
34
35
36
37
38
39
40
#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

Linus Torvalds's avatar
Linus Torvalds committed
41
/* return the number of _pages_ that will be allocated for the boot bitmap */
42
unsigned long __init bootmem_bootmap_pages(unsigned long pages)
Linus Torvalds's avatar
Linus Torvalds committed
43
44
45
46
47
48
49
50
51
{
	unsigned long mapsize;

	mapsize = (pages+7)/8;
	mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
	mapsize >>= PAGE_SHIFT;

	return mapsize;
}
52

53
54
55
/*
 * link bdata in order
 */
56
static void __init link_bootmem(bootmem_data_t *bdata)
57
58
{
	bootmem_data_t *ent;
59

60
61
62
63
64
65
66
67
68
69
70
71
72
73
	if (list_empty(&bdata_list)) {
		list_add(&bdata->list, &bdata_list);
		return;
	}
	/* insert in order */
	list_for_each_entry(ent, &bdata_list, list) {
		if (bdata->node_boot_start < ent->node_boot_start) {
			list_add_tail(&bdata->list, &ent->list);
			return;
		}
	}
	list_add_tail(&bdata->list, &bdata_list);
}

74
75
76
77
78
79
80
81
82
83
84
85
/*
 * Given an initialised bdata, it returns the size of the boot bitmap
 */
static unsigned long __init get_mapsize(bootmem_data_t *bdata)
{
	unsigned long mapsize;
	unsigned long start = PFN_DOWN(bdata->node_boot_start);
	unsigned long end = bdata->node_low_pfn;

	mapsize = ((end - start) + 7) / 8;
	return ALIGN(mapsize, sizeof(long));
}
Linus Torvalds's avatar
Linus Torvalds committed
86
87
88
89

/*
 * Called once to set up the allocator itself.
 */
90
static unsigned long __init init_bootmem_core(pg_data_t *pgdat,
Linus Torvalds's avatar
Linus Torvalds committed
91
92
93
	unsigned long mapstart, unsigned long start, unsigned long end)
{
	bootmem_data_t *bdata = pgdat->bdata;
94
	unsigned long mapsize;
Linus Torvalds's avatar
Linus Torvalds committed
95

96
97
	bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
	bdata->node_boot_start = PFN_PHYS(start);
Linus Torvalds's avatar
Linus Torvalds committed
98
	bdata->node_low_pfn = end;
99
	link_bootmem(bdata);
Linus Torvalds's avatar
Linus Torvalds committed
100
101
102
103
104

	/*
	 * Initially all pages are reserved - setup_arch() has to
	 * register free RAM areas explicitly.
	 */
105
	mapsize = get_mapsize(bdata);
Linus Torvalds's avatar
Linus Torvalds committed
106
107
108
109
110
111
112
113
114
115
	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.
 */
116
117
static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
					unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
118
{
119
	unsigned long sidx, eidx;
Linus Torvalds's avatar
Linus Torvalds committed
120
	unsigned long i;
121

Linus Torvalds's avatar
Linus Torvalds committed
122
123
124
125
126
	/*
	 * round up, partially reserved pages are considered
	 * fully reserved.
	 */
	BUG_ON(!size);
127
128
129
130
131
	BUG_ON(PFN_DOWN(addr) >= bdata->node_low_pfn);
	BUG_ON(PFN_UP(addr + size) > bdata->node_low_pfn);

	sidx = PFN_DOWN(addr - bdata->node_boot_start);
	eidx = PFN_UP(addr + size - bdata->node_boot_start);
Linus Torvalds's avatar
Linus Torvalds committed
132
133
134
135
136
137
138
139
140

	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
		}
}

141
142
static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
				     unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
143
{
144
	unsigned long sidx, eidx;
Linus Torvalds's avatar
Linus Torvalds committed
145
	unsigned long i;
146

Linus Torvalds's avatar
Linus Torvalds committed
147
148
149
150
151
	/*
	 * round down end of usable mem, partially free pages are
	 * considered reserved.
	 */
	BUG_ON(!size);
152
	BUG_ON(PFN_DOWN(addr + size) > bdata->node_low_pfn);
Linus Torvalds's avatar
Linus Torvalds committed
153
154
155
156
157
158
159

	if (addr < bdata->last_success)
		bdata->last_success = addr;

	/*
	 * Round up the beginning of the address.
	 */
160
161
	sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
	eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
Linus Torvalds's avatar
Linus Torvalds committed
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181

	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.
 */
182
void * __init
Linus Torvalds's avatar
Linus Torvalds committed
183
__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
184
	      unsigned long align, unsigned long goal, unsigned long limit)
Linus Torvalds's avatar
Linus Torvalds committed
185
186
{
	unsigned long offset, remaining_size, areasize, preferred;
187
	unsigned long i, start = 0, incr, eidx, end_pfn;
Linus Torvalds's avatar
Linus Torvalds committed
188
189
	void *ret;

190
	if (!size) {
Linus Torvalds's avatar
Linus Torvalds committed
191
192
193
194
195
		printk("__alloc_bootmem_core(): zero-sized request\n");
		BUG();
	}
	BUG_ON(align & (align-1));

196
197
198
	if (limit && bdata->node_boot_start >= limit)
		return NULL;

199
200
201
202
	/* on nodes without memory - bootmem_map is NULL */
	if (!bdata->node_bootmem_map)
		return NULL;

203
204
	end_pfn = bdata->node_low_pfn;
	limit = PFN_DOWN(limit);
205
206
207
	if (limit && end_pfn > limit)
		end_pfn = limit;

208
	eidx = end_pfn - PFN_DOWN(bdata->node_boot_start);
Linus Torvalds's avatar
Linus Torvalds committed
209
	offset = 0;
210
211
212
	if (align && (bdata->node_boot_start & (align - 1UL)) != 0)
		offset = align - (bdata->node_boot_start & (align - 1UL));
	offset = PFN_DOWN(offset);
Linus Torvalds's avatar
Linus Torvalds committed
213
214
215
216
217

	/*
	 * We try to allocate bootmem pages above 'goal'
	 * first, then we try to allocate lower pages.
	 */
218
	if (goal && goal >= bdata->node_boot_start && PFN_DOWN(goal) < end_pfn) {
Linus Torvalds's avatar
Linus Torvalds committed
219
220
221
		preferred = goal - bdata->node_boot_start;

		if (bdata->last_success >= preferred)
222
223
			if (!limit || (limit && limit > bdata->last_success))
				preferred = bdata->last_success;
Linus Torvalds's avatar
Linus Torvalds committed
224
225
226
	} else
		preferred = 0;

227
228
	preferred = PFN_DOWN(ALIGN(preferred, align)) + offset;
	areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
Linus Torvalds's avatar
Linus Torvalds committed
229
230
231
232
233
234
235
	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);
236
237
		if (i >= eidx)
			break;
Linus Torvalds's avatar
Linus Torvalds committed
238
239
240
241
242
		if (test_bit(i, bdata->node_bootmem_map))
			continue;
		for (j = i + 1; j < i + areasize; ++j) {
			if (j >= eidx)
				goto fail_block;
243
			if (test_bit(j, bdata->node_bootmem_map))
Linus Torvalds's avatar
Linus Torvalds committed
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
				goto fail_block;
		}
		start = i;
		goto found;
	fail_block:
		i = ALIGN(j, incr);
	}

	if (preferred > offset) {
		preferred = offset;
		goto restart_scan;
	}
	return NULL;

found:
259
	bdata->last_success = PFN_PHYS(start);
Linus Torvalds's avatar
Linus Torvalds committed
260
261
262
263
264
265
266
267
268
	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) {
269
		offset = ALIGN(bdata->last_offset, align);
Linus Torvalds's avatar
Linus Torvalds committed
270
		BUG_ON(offset > PAGE_SIZE);
271
		remaining_size = PAGE_SIZE - offset;
Linus Torvalds's avatar
Linus Torvalds committed
272
273
274
		if (size < remaining_size) {
			areasize = 0;
			/* last_pos unchanged */
275
276
277
278
			bdata->last_offset = offset + size;
			ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
					   offset +
					   bdata->node_boot_start);
Linus Torvalds's avatar
Linus Torvalds committed
279
280
		} else {
			remaining_size = size - remaining_size;
281
282
283
284
285
			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;
Linus Torvalds's avatar
Linus Torvalds committed
286
287
288
289
290
291
292
293
294
295
296
297
			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:
	 */
298
	for (i = start; i < start + areasize; i++)
Linus Torvalds's avatar
Linus Torvalds committed
299
300
301
302
303
304
305
306
307
		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;
308
	unsigned long pfn;
Linus Torvalds's avatar
Linus Torvalds committed
309
310
311
312
313
314
315
316
317
318
	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 */
319
320
	pfn = PFN_DOWN(bdata->node_boot_start);
	idx = bdata->node_low_pfn - pfn;
Linus Torvalds's avatar
Linus Torvalds committed
321
322
323
324
325
326
327
	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];
328

Linus Torvalds's avatar
Linus Torvalds committed
329
		if (gofast && v == ~0UL) {
330
			int order;
Linus Torvalds's avatar
Linus Torvalds committed
331

332
			page = pfn_to_page(pfn);
Linus Torvalds's avatar
Linus Torvalds committed
333
334
			count += BITS_PER_LONG;
			order = ffs(BITS_PER_LONG) - 1;
335
			__free_pages_bootmem(page, order);
Linus Torvalds's avatar
Linus Torvalds committed
336
337
338
339
			i += BITS_PER_LONG;
			page += BITS_PER_LONG;
		} else if (v) {
			unsigned long m;
340
341

			page = pfn_to_page(pfn);
Linus Torvalds's avatar
Linus Torvalds committed
342
343
344
			for (m = 1; m && i < idx; m<<=1, page++, i++) {
				if (v & m) {
					count++;
345
					__free_pages_bootmem(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
346
347
348
				}
			}
		} else {
349
			i += BITS_PER_LONG;
Linus Torvalds's avatar
Linus Torvalds committed
350
		}
351
		pfn += BITS_PER_LONG;
Linus Torvalds's avatar
Linus Torvalds committed
352
353
354
355
356
357
358
359
360
	}
	total += count;

	/*
	 * Now free the allocator bitmap itself, it's not
	 * needed anymore:
	 */
	page = virt_to_page(bdata->node_bootmem_map);
	count = 0;
361
362
	idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
	for (i = 0; i < idx; i++, page++) {
363
		__free_pages_bootmem(page, 0);
364
		count++;
Linus Torvalds's avatar
Linus Torvalds committed
365
366
367
368
369
370
371
	}
	total += count;
	bdata->node_bootmem_map = NULL;

	return total;
}

372
unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
373
				unsigned long startpfn, unsigned long endpfn)
Linus Torvalds's avatar
Linus Torvalds committed
374
{
375
	return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
Linus Torvalds's avatar
Linus Torvalds committed
376
377
}

378
379
void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
				 unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
380
381
382
383
{
	reserve_bootmem_core(pgdat->bdata, physaddr, size);
}

384
385
void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
			      unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
386
387
388
389
{
	free_bootmem_core(pgdat->bdata, physaddr, size);
}

390
unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
Linus Torvalds's avatar
Linus Torvalds committed
391
{
392
	return free_all_bootmem_core(pgdat);
Linus Torvalds's avatar
Linus Torvalds committed
393
394
}

395
unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
Linus Torvalds's avatar
Linus Torvalds committed
396
397
398
{
	max_low_pfn = pages;
	min_low_pfn = start;
399
	return init_bootmem_core(NODE_DATA(0), start, 0, pages);
Linus Torvalds's avatar
Linus Torvalds committed
400
401
402
}

#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
403
void __init reserve_bootmem(unsigned long addr, unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
404
405
406
407
408
{
	reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
}
#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */

409
void __init free_bootmem(unsigned long addr, unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
410
411
412
413
{
	free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
}

414
unsigned long __init free_all_bootmem(void)
Linus Torvalds's avatar
Linus Torvalds committed
415
{
416
	return free_all_bootmem_core(NODE_DATA(0));
Linus Torvalds's avatar
Linus Torvalds committed
417
418
}

419
420
void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
				      unsigned long goal)
Linus Torvalds's avatar
Linus Torvalds committed
421
{
422
	bootmem_data_t *bdata;
Linus Torvalds's avatar
Linus Torvalds committed
423
424
	void *ptr;

425
426
427
428
429
	list_for_each_entry(bdata, &bdata_list, list) {
		ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);
		if (ptr)
			return ptr;
	}
430
431
	return NULL;
}
Linus Torvalds's avatar
Linus Torvalds committed
432

433
434
void * __init __alloc_bootmem(unsigned long size, unsigned long align,
			      unsigned long goal)
435
436
{
	void *mem = __alloc_bootmem_nopanic(size,align,goal);
437

438
439
	if (mem)
		return mem;
Linus Torvalds's avatar
Linus Torvalds committed
440
441
442
443
444
445
446
447
	/*
	 * Whoops, we cannot satisfy the allocation request.
	 */
	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
	panic("Out of memory");
	return NULL;
}

448

449
450
void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
				   unsigned long align, unsigned long goal)
Linus Torvalds's avatar
Linus Torvalds committed
451
452
453
{
	void *ptr;

454
	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
Linus Torvalds's avatar
Linus Torvalds committed
455
	if (ptr)
456
		return ptr;
Linus Torvalds's avatar
Linus Torvalds committed
457

458
	return __alloc_bootmem(size, align, goal);
Linus Torvalds's avatar
Linus Torvalds committed
459
460
}

461
462
463
#ifndef ARCH_LOW_ADDRESS_LIMIT
#define ARCH_LOW_ADDRESS_LIMIT	0xffffffffUL
#endif
464

465
466
void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
				  unsigned long goal)
467
{
468
	bootmem_data_t *bdata;
469
470
	void *ptr;

471
	list_for_each_entry(bdata, &bdata_list, list) {
472
473
		ptr = __alloc_bootmem_core(bdata, size, align, goal,
						ARCH_LOW_ADDRESS_LIMIT);
474
475
476
		if (ptr)
			return ptr;
	}
477
478
479
480
481
482
483
484
485
486
487
488

	/*
	 * 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)
{
489
490
	return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
				    ARCH_LOW_ADDRESS_LIMIT);
491
}