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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/bootmem.c
3 *
4 * Copyright (C) 1999 Ingo Molnar
5 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
6 *
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.
10 */
11
12#include <linux/mm.h>
13#include <linux/kernel_stat.h>
14#include <linux/swap.h>
15#include <linux/interrupt.h>
16#include <linux/init.h>
17#include <linux/bootmem.h>
18#include <linux/mmzone.h>
19#include <linux/module.h>
20#include <asm/dma.h>
21#include <asm/io.h>
22#include "internal.h"
23
24/*
25 * Access to this subsystem has to be serialized externally. (this is
26 * true for the boot process anyway)
27 */
28unsigned long max_low_pfn;
29unsigned long min_low_pfn;
30unsigned long max_pfn;
31
32EXPORT_SYMBOL(max_pfn); /* This is exported so
33 * dma_get_required_mask(), which uses
34 * it, can be an inline function */
35
Vivek Goyal92aa63a2005-06-25 14:58:18 -070036#ifdef CONFIG_CRASH_DUMP
37/*
38 * If we have booted due to a crash, max_pfn will be a very low value. We need
39 * to know the amount of memory that the previous kernel used.
40 */
41unsigned long saved_max_pfn;
42#endif
43
Linus Torvalds1da177e2005-04-16 15:20:36 -070044/* return the number of _pages_ that will be allocated for the boot bitmap */
45unsigned long __init bootmem_bootmap_pages (unsigned long pages)
46{
47 unsigned long mapsize;
48
49 mapsize = (pages+7)/8;
50 mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
51 mapsize >>= PAGE_SHIFT;
52
53 return mapsize;
54}
55
56/*
57 * Called once to set up the allocator itself.
58 */
59static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
60 unsigned long mapstart, unsigned long start, unsigned long end)
61{
62 bootmem_data_t *bdata = pgdat->bdata;
63 unsigned long mapsize = ((end - start)+7)/8;
64
65 pgdat->pgdat_next = pgdat_list;
66 pgdat_list = pgdat;
67
Nick Wilson8c0e33c2005-06-25 14:59:00 -070068 mapsize = ALIGN(mapsize, sizeof(long));
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
70 bdata->node_boot_start = (start << PAGE_SHIFT);
71 bdata->node_low_pfn = end;
72
73 /*
74 * Initially all pages are reserved - setup_arch() has to
75 * register free RAM areas explicitly.
76 */
77 memset(bdata->node_bootmem_map, 0xff, mapsize);
78
79 return mapsize;
80}
81
82/*
83 * Marks a particular physical memory range as unallocatable. Usable RAM
84 * might be used for boot-time allocations - or it might get added
85 * to the free page pool later on.
86 */
87static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
88{
89 unsigned long i;
90 /*
91 * round up, partially reserved pages are considered
92 * fully reserved.
93 */
94 unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
95 unsigned long eidx = (addr + size - bdata->node_boot_start +
96 PAGE_SIZE-1)/PAGE_SIZE;
97 unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
98
99 BUG_ON(!size);
100 BUG_ON(sidx >= eidx);
101 BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
102 BUG_ON(end > bdata->node_low_pfn);
103
104 for (i = sidx; i < eidx; i++)
105 if (test_and_set_bit(i, bdata->node_bootmem_map)) {
106#ifdef CONFIG_DEBUG_BOOTMEM
107 printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
108#endif
109 }
110}
111
112static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
113{
114 unsigned long i;
115 unsigned long start;
116 /*
117 * round down end of usable mem, partially free pages are
118 * considered reserved.
119 */
120 unsigned long sidx;
121 unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
122 unsigned long end = (addr + size)/PAGE_SIZE;
123
124 BUG_ON(!size);
125 BUG_ON(end > bdata->node_low_pfn);
126
127 if (addr < bdata->last_success)
128 bdata->last_success = addr;
129
130 /*
131 * Round up the beginning of the address.
132 */
133 start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
134 sidx = start - (bdata->node_boot_start/PAGE_SIZE);
135
136 for (i = sidx; i < eidx; i++) {
137 if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
138 BUG();
139 }
140}
141
142/*
143 * We 'merge' subsequent allocations to save space. We might 'lose'
144 * some fraction of a page if allocations cannot be satisfied due to
145 * size constraints on boxes where there is physical RAM space
146 * fragmentation - in these cases (mostly large memory boxes) this
147 * is not a problem.
148 *
149 * On low memory boxes we get it right in 100% of the cases.
150 *
151 * alignment has to be a power of 2 value.
152 *
153 * NOTE: This function is _not_ reentrant.
154 */
155static void * __init
156__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
157 unsigned long align, unsigned long goal)
158{
159 unsigned long offset, remaining_size, areasize, preferred;
160 unsigned long i, start = 0, incr, eidx;
161 void *ret;
162
163 if(!size) {
164 printk("__alloc_bootmem_core(): zero-sized request\n");
165 BUG();
166 }
167 BUG_ON(align & (align-1));
168
169 eidx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
170 offset = 0;
171 if (align &&
172 (bdata->node_boot_start & (align - 1UL)) != 0)
173 offset = (align - (bdata->node_boot_start & (align - 1UL)));
174 offset >>= PAGE_SHIFT;
175
176 /*
177 * We try to allocate bootmem pages above 'goal'
178 * first, then we try to allocate lower pages.
179 */
180 if (goal && (goal >= bdata->node_boot_start) &&
181 ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
182 preferred = goal - bdata->node_boot_start;
183
184 if (bdata->last_success >= preferred)
185 preferred = bdata->last_success;
186 } else
187 preferred = 0;
188
Nick Wilson8c0e33c2005-06-25 14:59:00 -0700189 preferred = ALIGN(preferred, align) >> PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 preferred += offset;
191 areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
192 incr = align >> PAGE_SHIFT ? : 1;
193
194restart_scan:
195 for (i = preferred; i < eidx; i += incr) {
196 unsigned long j;
197 i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
198 i = ALIGN(i, incr);
199 if (test_bit(i, bdata->node_bootmem_map))
200 continue;
201 for (j = i + 1; j < i + areasize; ++j) {
202 if (j >= eidx)
203 goto fail_block;
204 if (test_bit (j, bdata->node_bootmem_map))
205 goto fail_block;
206 }
207 start = i;
208 goto found;
209 fail_block:
210 i = ALIGN(j, incr);
211 }
212
213 if (preferred > offset) {
214 preferred = offset;
215 goto restart_scan;
216 }
217 return NULL;
218
219found:
220 bdata->last_success = start << PAGE_SHIFT;
221 BUG_ON(start >= eidx);
222
223 /*
224 * Is the next page of the previous allocation-end the start
225 * of this allocation's buffer? If yes then we can 'merge'
226 * the previous partial page with this allocation.
227 */
228 if (align < PAGE_SIZE &&
229 bdata->last_offset && bdata->last_pos+1 == start) {
Nick Wilson8c0e33c2005-06-25 14:59:00 -0700230 offset = ALIGN(bdata->last_offset, align);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 BUG_ON(offset > PAGE_SIZE);
232 remaining_size = PAGE_SIZE-offset;
233 if (size < remaining_size) {
234 areasize = 0;
235 /* last_pos unchanged */
236 bdata->last_offset = offset+size;
237 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
238 bdata->node_boot_start);
239 } else {
240 remaining_size = size - remaining_size;
241 areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
242 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
243 bdata->node_boot_start);
244 bdata->last_pos = start+areasize-1;
245 bdata->last_offset = remaining_size;
246 }
247 bdata->last_offset &= ~PAGE_MASK;
248 } else {
249 bdata->last_pos = start + areasize - 1;
250 bdata->last_offset = size & ~PAGE_MASK;
251 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
252 }
253
254 /*
255 * Reserve the area now:
256 */
257 for (i = start; i < start+areasize; i++)
258 if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
259 BUG();
260 memset(ret, 0, size);
261 return ret;
262}
263
264static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
265{
266 struct page *page;
Andy Whitcroftd41dee32005-06-23 00:07:54 -0700267 unsigned long pfn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 bootmem_data_t *bdata = pgdat->bdata;
269 unsigned long i, count, total = 0;
270 unsigned long idx;
271 unsigned long *map;
272 int gofast = 0;
273
274 BUG_ON(!bdata->node_bootmem_map);
275
276 count = 0;
277 /* first extant page of the node */
Andy Whitcroftd41dee32005-06-23 00:07:54 -0700278 pfn = bdata->node_boot_start >> PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
280 map = bdata->node_bootmem_map;
281 /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
282 if (bdata->node_boot_start == 0 ||
283 ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
284 gofast = 1;
285 for (i = 0; i < idx; ) {
286 unsigned long v = ~map[i / BITS_PER_LONG];
Andy Whitcroftd41dee32005-06-23 00:07:54 -0700287
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 if (gofast && v == ~0UL) {
289 int j, order;
290
Andy Whitcroftd41dee32005-06-23 00:07:54 -0700291 page = pfn_to_page(pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 count += BITS_PER_LONG;
293 __ClearPageReserved(page);
294 order = ffs(BITS_PER_LONG) - 1;
295 set_page_refs(page, order);
296 for (j = 1; j < BITS_PER_LONG; j++) {
297 if (j + 16 < BITS_PER_LONG)
298 prefetchw(page + j + 16);
299 __ClearPageReserved(page + j);
300 }
301 __free_pages(page, order);
302 i += BITS_PER_LONG;
303 page += BITS_PER_LONG;
304 } else if (v) {
305 unsigned long m;
Andy Whitcroftd41dee32005-06-23 00:07:54 -0700306
307 page = pfn_to_page(pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 for (m = 1; m && i < idx; m<<=1, page++, i++) {
309 if (v & m) {
310 count++;
311 __ClearPageReserved(page);
312 set_page_refs(page, 0);
313 __free_page(page);
314 }
315 }
316 } else {
317 i+=BITS_PER_LONG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 }
Andy Whitcroftd41dee32005-06-23 00:07:54 -0700319 pfn += BITS_PER_LONG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 }
321 total += count;
322
323 /*
324 * Now free the allocator bitmap itself, it's not
325 * needed anymore:
326 */
327 page = virt_to_page(bdata->node_bootmem_map);
328 count = 0;
329 for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
330 count++;
331 __ClearPageReserved(page);
332 set_page_count(page, 1);
333 __free_page(page);
334 }
335 total += count;
336 bdata->node_bootmem_map = NULL;
337
338 return total;
339}
340
341unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
342{
343 return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
344}
345
346void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
347{
348 reserve_bootmem_core(pgdat->bdata, physaddr, size);
349}
350
351void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
352{
353 free_bootmem_core(pgdat->bdata, physaddr, size);
354}
355
356unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
357{
358 return(free_all_bootmem_core(pgdat));
359}
360
361unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
362{
363 max_low_pfn = pages;
364 min_low_pfn = start;
365 return(init_bootmem_core(NODE_DATA(0), start, 0, pages));
366}
367
368#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
369void __init reserve_bootmem (unsigned long addr, unsigned long size)
370{
371 reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
372}
373#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
374
375void __init free_bootmem (unsigned long addr, unsigned long size)
376{
377 free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
378}
379
380unsigned long __init free_all_bootmem (void)
381{
382 return(free_all_bootmem_core(NODE_DATA(0)));
383}
384
385void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
386{
387 pg_data_t *pgdat = pgdat_list;
388 void *ptr;
389
390 for_each_pgdat(pgdat)
391 if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
392 align, goal)))
393 return(ptr);
394
395 /*
396 * Whoops, we cannot satisfy the allocation request.
397 */
398 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
399 panic("Out of memory");
400 return NULL;
401}
402
403void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal)
404{
405 void *ptr;
406
407 ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal);
408 if (ptr)
409 return (ptr);
410
411 return __alloc_bootmem(size, align, goal);
412}
413