bootmem.c 11.1 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
37
38
39
40
41
42
43
#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
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
/* 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;
}

/*
 * 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;

65
66
	pgdat->pgdat_next = pgdat_list;
	pgdat_list = pgdat;
Linus Torvalds's avatar
Linus Torvalds committed
67

68
	mapsize = ALIGN(mapsize, sizeof(long));
Linus Torvalds's avatar
Linus Torvalds committed
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
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
	bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
	bdata->node_boot_start = (start << PAGE_SHIFT);
	bdata->node_low_pfn = end;

	/*
	 * 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.
 */
static void * __init
__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
157
	      unsigned long align, unsigned long goal, unsigned long limit)
Linus Torvalds's avatar
Linus Torvalds committed
158
159
{
	unsigned long offset, remaining_size, areasize, preferred;
160
	unsigned long i, start = 0, incr, eidx, end_pfn = bdata->node_low_pfn;
Linus Torvalds's avatar
Linus Torvalds committed
161
162
163
164
165
166
167
168
	void *ret;

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

169
170
171
172
173
174
175
176
	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
177
178
179
180
181
182
183
184
185
186
187
	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) && 
188
	    ((goal >> PAGE_SHIFT) < end_pfn)) {
Linus Torvalds's avatar
Linus Torvalds committed
189
190
191
		preferred = goal - bdata->node_boot_start;

		if (bdata->last_success >= preferred)
192
193
			if (!limit || (limit && limit > bdata->last_success))
				preferred = bdata->last_success;
Linus Torvalds's avatar
Linus Torvalds committed
194
195
196
	} else
		preferred = 0;

197
	preferred = ALIGN(preferred, align) >> PAGE_SHIFT;
Linus Torvalds's avatar
Linus Torvalds committed
198
199
200
201
202
203
204
205
206
	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);
207
208
		if (i >= eidx)
			break;
Linus Torvalds's avatar
Linus Torvalds committed
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
		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) {
240
		offset = ALIGN(bdata->last_offset, align);
Linus Torvalds's avatar
Linus Torvalds committed
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
		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;
277
	unsigned long pfn;
Linus Torvalds's avatar
Linus Torvalds committed
278
279
280
281
282
283
284
285
286
287
	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 */
288
	pfn = bdata->node_boot_start >> PAGE_SHIFT;
Linus Torvalds's avatar
Linus Torvalds committed
289
290
291
292
293
294
295
296
	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];
297

Linus Torvalds's avatar
Linus Torvalds committed
298
299
300
		if (gofast && v == ~0UL) {
			int j, order;

301
			page = pfn_to_page(pfn);
Linus Torvalds's avatar
Linus Torvalds committed
302
303
304
305
306
307
308
309
			count += BITS_PER_LONG;
			__ClearPageReserved(page);
			order = ffs(BITS_PER_LONG) - 1;
			set_page_refs(page, order);
			for (j = 1; j < BITS_PER_LONG; j++) {
				if (j + 16 < BITS_PER_LONG)
					prefetchw(page + j + 16);
				__ClearPageReserved(page + j);
Nick Piggin's avatar
Nick Piggin committed
310
				set_page_count(page + j, 0);
Linus Torvalds's avatar
Linus Torvalds committed
311
312
313
314
315
316
			}
			__free_pages(page, order);
			i += BITS_PER_LONG;
			page += BITS_PER_LONG;
		} else if (v) {
			unsigned long m;
317
318

			page = pfn_to_page(pfn);
Linus Torvalds's avatar
Linus Torvalds committed
319
320
321
322
323
324
325
326
327
328
329
			for (m = 1; m && i < idx; m<<=1, page++, i++) {
				if (v & m) {
					count++;
					__ClearPageReserved(page);
					set_page_refs(page, 0);
					__free_page(page);
				}
			}
		} else {
			i+=BITS_PER_LONG;
		}
330
		pfn += BITS_PER_LONG;
Linus Torvalds's avatar
Linus Torvalds committed
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
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
	}
	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++;
		__ClearPageReserved(page);
		set_page_count(page, 1);
		__free_page(page);
	}
	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)));
}

396
397
void * __init __alloc_bootmem_limit (unsigned long size, unsigned long align, unsigned long goal,
				unsigned long limit)
Linus Torvalds's avatar
Linus Torvalds committed
398
399
400
401
402
403
{
	pg_data_t *pgdat = pgdat_list;
	void *ptr;

	for_each_pgdat(pgdat)
		if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
404
						 align, goal, limit)))
Linus Torvalds's avatar
Linus Torvalds committed
405
406
407
408
409
410
411
412
413
414
			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;
}

415
416
417

void * __init __alloc_bootmem_node_limit (pg_data_t *pgdat, unsigned long size, unsigned long align,
				     unsigned long goal, unsigned long limit)
Linus Torvalds's avatar
Linus Torvalds committed
418
419
420
{
	void *ptr;

421
	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, limit);
Linus Torvalds's avatar
Linus Torvalds committed
422
423
424
	if (ptr)
		return (ptr);

425
	return __alloc_bootmem_limit(size, align, goal, limit);
Linus Torvalds's avatar
Linus Torvalds committed
426
427
}