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-rw-r--r--mm/bootmem.c400
1 files changed, 400 insertions, 0 deletions
diff --git a/mm/bootmem.c b/mm/bootmem.c
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1/*
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
36/* return the number of _pages_ that will be allocated for the boot bitmap */
37unsigned long __init bootmem_bootmap_pages (unsigned long pages)
38{
39 unsigned long mapsize;
40
41 mapsize = (pages+7)/8;
42 mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
43 mapsize >>= PAGE_SHIFT;
44
45 return mapsize;
46}
47
48/*
49 * Called once to set up the allocator itself.
50 */
51static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
52 unsigned long mapstart, unsigned long start, unsigned long end)
53{
54 bootmem_data_t *bdata = pgdat->bdata;
55 unsigned long mapsize = ((end - start)+7)/8;
56
57 pgdat->pgdat_next = pgdat_list;
58 pgdat_list = pgdat;
59
60 mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
61 bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
62 bdata->node_boot_start = (start << PAGE_SHIFT);
63 bdata->node_low_pfn = end;
64
65 /*
66 * Initially all pages are reserved - setup_arch() has to
67 * register free RAM areas explicitly.
68 */
69 memset(bdata->node_bootmem_map, 0xff, mapsize);
70
71 return mapsize;
72}
73
74/*
75 * Marks a particular physical memory range as unallocatable. Usable RAM
76 * might be used for boot-time allocations - or it might get added
77 * to the free page pool later on.
78 */
79static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
80{
81 unsigned long i;
82 /*
83 * round up, partially reserved pages are considered
84 * fully reserved.
85 */
86 unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
87 unsigned long eidx = (addr + size - bdata->node_boot_start +
88 PAGE_SIZE-1)/PAGE_SIZE;
89 unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
90
91 BUG_ON(!size);
92 BUG_ON(sidx >= eidx);
93 BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
94 BUG_ON(end > bdata->node_low_pfn);
95
96 for (i = sidx; i < eidx; i++)
97 if (test_and_set_bit(i, bdata->node_bootmem_map)) {
98#ifdef CONFIG_DEBUG_BOOTMEM
99 printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
100#endif
101 }
102}
103
104static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
105{
106 unsigned long i;
107 unsigned long start;
108 /*
109 * round down end of usable mem, partially free pages are
110 * considered reserved.
111 */
112 unsigned long sidx;
113 unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
114 unsigned long end = (addr + size)/PAGE_SIZE;
115
116 BUG_ON(!size);
117 BUG_ON(end > bdata->node_low_pfn);
118
119 if (addr < bdata->last_success)
120 bdata->last_success = addr;
121
122 /*
123 * Round up the beginning of the address.
124 */
125 start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
126 sidx = start - (bdata->node_boot_start/PAGE_SIZE);
127
128 for (i = sidx; i < eidx; i++) {
129 if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
130 BUG();
131 }
132}
133
134/*
135 * We 'merge' subsequent allocations to save space. We might 'lose'
136 * some fraction of a page if allocations cannot be satisfied due to
137 * size constraints on boxes where there is physical RAM space
138 * fragmentation - in these cases (mostly large memory boxes) this
139 * is not a problem.
140 *
141 * On low memory boxes we get it right in 100% of the cases.
142 *
143 * alignment has to be a power of 2 value.
144 *
145 * NOTE: This function is _not_ reentrant.
146 */
147static void * __init
148__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
149 unsigned long align, unsigned long goal)
150{
151 unsigned long offset, remaining_size, areasize, preferred;
152 unsigned long i, start = 0, incr, eidx;
153 void *ret;
154
155 if(!size) {
156 printk("__alloc_bootmem_core(): zero-sized request\n");
157 BUG();
158 }
159 BUG_ON(align & (align-1));
160
161 eidx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
162 offset = 0;
163 if (align &&
164 (bdata->node_boot_start & (align - 1UL)) != 0)
165 offset = (align - (bdata->node_boot_start & (align - 1UL)));
166 offset >>= PAGE_SHIFT;
167
168 /*
169 * We try to allocate bootmem pages above 'goal'
170 * first, then we try to allocate lower pages.
171 */
172 if (goal && (goal >= bdata->node_boot_start) &&
173 ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
174 preferred = goal - bdata->node_boot_start;
175
176 if (bdata->last_success >= preferred)
177 preferred = bdata->last_success;
178 } else
179 preferred = 0;
180
181 preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
182 preferred += offset;
183 areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
184 incr = align >> PAGE_SHIFT ? : 1;
185
186restart_scan:
187 for (i = preferred; i < eidx; i += incr) {
188 unsigned long j;
189 i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
190 i = ALIGN(i, incr);
191 if (test_bit(i, bdata->node_bootmem_map))
192 continue;
193 for (j = i + 1; j < i + areasize; ++j) {
194 if (j >= eidx)
195 goto fail_block;
196 if (test_bit (j, bdata->node_bootmem_map))
197 goto fail_block;
198 }
199 start = i;
200 goto found;
201 fail_block:
202 i = ALIGN(j, incr);
203 }
204
205 if (preferred > offset) {
206 preferred = offset;
207 goto restart_scan;
208 }
209 return NULL;
210
211found:
212 bdata->last_success = start << PAGE_SHIFT;
213 BUG_ON(start >= eidx);
214
215 /*
216 * Is the next page of the previous allocation-end the start
217 * of this allocation's buffer? If yes then we can 'merge'
218 * the previous partial page with this allocation.
219 */
220 if (align < PAGE_SIZE &&
221 bdata->last_offset && bdata->last_pos+1 == start) {
222 offset = (bdata->last_offset+align-1) & ~(align-1);
223 BUG_ON(offset > PAGE_SIZE);
224 remaining_size = PAGE_SIZE-offset;
225 if (size < remaining_size) {
226 areasize = 0;
227 /* last_pos unchanged */
228 bdata->last_offset = offset+size;
229 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
230 bdata->node_boot_start);
231 } else {
232 remaining_size = size - remaining_size;
233 areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
234 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
235 bdata->node_boot_start);
236 bdata->last_pos = start+areasize-1;
237 bdata->last_offset = remaining_size;
238 }
239 bdata->last_offset &= ~PAGE_MASK;
240 } else {
241 bdata->last_pos = start + areasize - 1;
242 bdata->last_offset = size & ~PAGE_MASK;
243 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
244 }
245
246 /*
247 * Reserve the area now:
248 */
249 for (i = start; i < start+areasize; i++)
250 if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
251 BUG();
252 memset(ret, 0, size);
253 return ret;
254}
255
256static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
257{
258 struct page *page;
259 bootmem_data_t *bdata = pgdat->bdata;
260 unsigned long i, count, total = 0;
261 unsigned long idx;
262 unsigned long *map;
263 int gofast = 0;
264
265 BUG_ON(!bdata->node_bootmem_map);
266
267 count = 0;
268 /* first extant page of the node */
269 page = virt_to_page(phys_to_virt(bdata->node_boot_start));
270 idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
271 map = bdata->node_bootmem_map;
272 /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
273 if (bdata->node_boot_start == 0 ||
274 ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
275 gofast = 1;
276 for (i = 0; i < idx; ) {
277 unsigned long v = ~map[i / BITS_PER_LONG];
278 if (gofast && v == ~0UL) {
279 int j, order;
280
281 count += BITS_PER_LONG;
282 __ClearPageReserved(page);
283 order = ffs(BITS_PER_LONG) - 1;
284 set_page_refs(page, order);
285 for (j = 1; j < BITS_PER_LONG; j++) {
286 if (j + 16 < BITS_PER_LONG)
287 prefetchw(page + j + 16);
288 __ClearPageReserved(page + j);
289 }
290 __free_pages(page, order);
291 i += BITS_PER_LONG;
292 page += BITS_PER_LONG;
293 } else if (v) {
294 unsigned long m;
295 for (m = 1; m && i < idx; m<<=1, page++, i++) {
296 if (v & m) {
297 count++;
298 __ClearPageReserved(page);
299 set_page_refs(page, 0);
300 __free_page(page);
301 }
302 }
303 } else {
304 i+=BITS_PER_LONG;
305 page += BITS_PER_LONG;
306 }
307 }
308 total += count;
309
310 /*
311 * Now free the allocator bitmap itself, it's not
312 * needed anymore:
313 */
314 page = virt_to_page(bdata->node_bootmem_map);
315 count = 0;
316 for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
317 count++;
318 __ClearPageReserved(page);
319 set_page_count(page, 1);
320 __free_page(page);
321 }
322 total += count;
323 bdata->node_bootmem_map = NULL;
324
325 return total;
326}
327
328unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
329{
330 return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
331}
332
333void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
334{
335 reserve_bootmem_core(pgdat->bdata, physaddr, size);
336}
337
338void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
339{
340 free_bootmem_core(pgdat->bdata, physaddr, size);
341}
342
343unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
344{
345 return(free_all_bootmem_core(pgdat));
346}
347
348unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
349{
350 max_low_pfn = pages;
351 min_low_pfn = start;
352 return(init_bootmem_core(NODE_DATA(0), start, 0, pages));
353}
354
355#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
356void __init reserve_bootmem (unsigned long addr, unsigned long size)
357{
358 reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
359}
360#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
361
362void __init free_bootmem (unsigned long addr, unsigned long size)
363{
364 free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
365}
366
367unsigned long __init free_all_bootmem (void)
368{
369 return(free_all_bootmem_core(NODE_DATA(0)));
370}
371
372void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
373{
374 pg_data_t *pgdat = pgdat_list;
375 void *ptr;
376
377 for_each_pgdat(pgdat)
378 if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
379 align, goal)))
380 return(ptr);
381
382 /*
383 * Whoops, we cannot satisfy the allocation request.
384 */
385 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
386 panic("Out of memory");
387 return NULL;
388}
389
390void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal)
391{
392 void *ptr;
393
394 ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal);
395 if (ptr)
396 return (ptr);
397
398 return __alloc_bootmem(size, align, goal);
399}
400
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