bootmem.c 11.8 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
/*
 *  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/mm.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <asm/dma.h>
#include <asm/io.h>
#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;

EXPORT_SYMBOL(max_pfn);		/* This is exported so
				 * dma_get_required_mask(), which uses
				 * it, can be an inline function */

36
static LIST_HEAD(bdata_list);
37
38
39
40
41
42
43
44
#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
45
46
47
48
49
50
51
52
53
54
55
/* return the number of _pages_ that will be allocated for the boot bitmap */
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;

	return mapsize;
}
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
/*
 * link bdata in order
 */
static void link_bootmem(bootmem_data_t *bdata)
{
	bootmem_data_t *ent;
	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);
	return;
}

Linus Torvalds's avatar
Linus Torvalds committed
77
78
79
80
81
82
83
84
85
86

/*
 * Called once to set up the allocator itself.
 */
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;

87
	mapsize = ALIGN(mapsize, sizeof(long));
Linus Torvalds's avatar
Linus Torvalds committed
88
89
90
	bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
	bdata->node_boot_start = (start << PAGE_SHIFT);
	bdata->node_low_pfn = end;
91
	link_bootmem(bdata);
Linus Torvalds's avatar
Linus Torvalds committed
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174

	/*
	 * Initially all pages are reserved - setup_arch() has to
	 * register free RAM areas explicitly.
	 */
	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.
 */
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;

	BUG_ON(!size);
	BUG_ON(sidx >= eidx);
	BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
	BUG_ON(end > bdata->node_low_pfn);

	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
		}
}

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;

	BUG_ON(!size);
	BUG_ON(end > bdata->node_low_pfn);

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

	/*
	 * Round up the beginning of the address.
	 */
	start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
	sidx = start - (bdata->node_boot_start/PAGE_SIZE);

	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.
 */
175
void * __init
Linus Torvalds's avatar
Linus Torvalds committed
176
__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
177
	      unsigned long align, unsigned long goal, unsigned long limit)
Linus Torvalds's avatar
Linus Torvalds committed
178
179
{
	unsigned long offset, remaining_size, areasize, preferred;
180
	unsigned long i, start = 0, incr, eidx, end_pfn = bdata->node_low_pfn;
Linus Torvalds's avatar
Linus Torvalds committed
181
182
183
184
185
186
187
188
	void *ret;

	if(!size) {
		printk("__alloc_bootmem_core(): zero-sized request\n");
		BUG();
	}
	BUG_ON(align & (align-1));

189
190
191
192
193
194
195
196
	if (limit && bdata->node_boot_start >= limit)
		return NULL;

        limit >>=PAGE_SHIFT;
	if (limit && end_pfn > limit)
		end_pfn = limit;

	eidx = end_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
Linus Torvalds's avatar
Linus Torvalds committed
197
198
199
200
201
202
203
204
205
206
207
	offset = 0;
	if (align &&
	    (bdata->node_boot_start & (align - 1UL)) != 0)
		offset = (align - (bdata->node_boot_start & (align - 1UL)));
	offset >>= PAGE_SHIFT;

	/*
	 * We try to allocate bootmem pages above 'goal'
	 * first, then we try to allocate lower pages.
	 */
	if (goal && (goal >= bdata->node_boot_start) && 
208
	    ((goal >> PAGE_SHIFT) < end_pfn)) {
Linus Torvalds's avatar
Linus Torvalds committed
209
210
211
		preferred = goal - bdata->node_boot_start;

		if (bdata->last_success >= preferred)
212
213
			if (!limit || (limit && limit > bdata->last_success))
				preferred = bdata->last_success;
Linus Torvalds's avatar
Linus Torvalds committed
214
215
216
	} else
		preferred = 0;

217
	preferred = ALIGN(preferred, align) >> PAGE_SHIFT;
Linus Torvalds's avatar
Linus Torvalds committed
218
219
220
221
222
223
224
225
226
	preferred += offset;
	areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
	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);
227
228
		if (i >= eidx)
			break;
Linus Torvalds's avatar
Linus Torvalds committed
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
		if (test_bit(i, bdata->node_bootmem_map))
			continue;
		for (j = i + 1; j < i + areasize; ++j) {
			if (j >= eidx)
				goto fail_block;
			if (test_bit (j, bdata->node_bootmem_map))
				goto fail_block;
		}
		start = i;
		goto found;
	fail_block:
		i = ALIGN(j, incr);
	}

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

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

Linus Torvalds's avatar
Linus Torvalds committed
318
		if (gofast && v == ~0UL) {
319
			int order;
Linus Torvalds's avatar
Linus Torvalds committed
320

321
			page = pfn_to_page(pfn);
Linus Torvalds's avatar
Linus Torvalds committed
322
323
			count += BITS_PER_LONG;
			order = ffs(BITS_PER_LONG) - 1;
324
			__free_pages_bootmem(page, order);
Linus Torvalds's avatar
Linus Torvalds committed
325
326
327
328
			i += BITS_PER_LONG;
			page += BITS_PER_LONG;
		} else if (v) {
			unsigned long m;
329
330

			page = pfn_to_page(pfn);
Linus Torvalds's avatar
Linus Torvalds committed
331
332
333
			for (m = 1; m && i < idx; m<<=1, page++, i++) {
				if (v & m) {
					count++;
334
					__free_pages_bootmem(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
335
336
337
338
339
				}
			}
		} else {
			i+=BITS_PER_LONG;
		}
340
		pfn += BITS_PER_LONG;
Linus Torvalds's avatar
Linus Torvalds committed
341
342
343
344
345
346
347
348
349
350
351
	}
	total += count;

	/*
	 * Now free the allocator bitmap itself, it's not
	 * needed anymore:
	 */
	page = virt_to_page(bdata->node_bootmem_map);
	count = 0;
	for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
		count++;
352
		__free_pages_bootmem(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
	}
	total += count;
	bdata->node_bootmem_map = NULL;

	return total;
}

unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
{
	return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
}

void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
{
	reserve_bootmem_core(pgdat->bdata, physaddr, size);
}

void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
{
	free_bootmem_core(pgdat->bdata, physaddr, size);
}

unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
{
	return(free_all_bootmem_core(pgdat));
}

unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
{
	max_low_pfn = pages;
	min_low_pfn = start;
	return(init_bootmem_core(NODE_DATA(0), start, 0, pages));
}

#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
void __init reserve_bootmem (unsigned long addr, unsigned long size)
{
	reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
}
#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */

void __init free_bootmem (unsigned long addr, unsigned long size)
{
	free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
}

unsigned long __init free_all_bootmem (void)
{
	return(free_all_bootmem_core(NODE_DATA(0)));
}

404
void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal)
Linus Torvalds's avatar
Linus Torvalds committed
405
{
406
	bootmem_data_t *bdata;
Linus Torvalds's avatar
Linus Torvalds committed
407
408
	void *ptr;

409
410
	list_for_each_entry(bdata, &bdata_list, list)
		if ((ptr = __alloc_bootmem_core(bdata, size, align, goal, 0)))
Linus Torvalds's avatar
Linus Torvalds committed
411
412
413
414
415
416
417
418
419
420
			return(ptr);

	/*
	 * Whoops, we cannot satisfy the allocation request.
	 */
	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
	panic("Out of memory");
	return NULL;
}

421

422
423
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
424
425
426
{
	void *ptr;

427
	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
Linus Torvalds's avatar
Linus Torvalds committed
428
429
430
	if (ptr)
		return (ptr);

431
	return __alloc_bootmem(size, align, goal);
Linus Torvalds's avatar
Linus Torvalds committed
432
433
}

434
435
436
437
#define LOW32LIMIT 0xffffffff

void * __init __alloc_bootmem_low(unsigned long size, unsigned long align, unsigned long goal)
{
438
	bootmem_data_t *bdata;
439
440
	void *ptr;

441
442
	list_for_each_entry(bdata, &bdata_list, list)
		if ((ptr = __alloc_bootmem_core(bdata, size,
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
						 align, goal, LOW32LIMIT)))
			return(ptr);

	/*
	 * 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)
{
	return __alloc_bootmem_core(pgdat->bdata, size, align, goal, LOW32LIMIT);
}