4 * Copyright (C) 1999 Ingo Molnar
5 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
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.
11 #include <linux/init.h>
12 #include <linux/pfn.h>
13 #include <linux/bootmem.h>
14 #include <linux/module.h>
18 #include <asm/processor.h>
23 * Access to this subsystem has to be serialized externally. (this is
24 * true for the boot process anyway)
26 unsigned long max_low_pfn
;
27 unsigned long min_low_pfn
;
28 unsigned long max_pfn
;
30 static LIST_HEAD(bdata_list
);
31 #ifdef CONFIG_CRASH_DUMP
33 * If we have booted due to a crash, max_pfn will be a very low value. We need
34 * to know the amount of memory that the previous kernel used.
36 unsigned long saved_max_pfn
;
39 /* return the number of _pages_ that will be allocated for the boot bitmap */
40 unsigned long __init
bootmem_bootmap_pages(unsigned long pages
)
42 unsigned long mapsize
;
44 mapsize
= (pages
+7)/8;
45 mapsize
= (mapsize
+ ~PAGE_MASK
) & PAGE_MASK
;
46 mapsize
>>= PAGE_SHIFT
;
54 static void __init
link_bootmem(bootmem_data_t
*bdata
)
58 if (list_empty(&bdata_list
)) {
59 list_add(&bdata
->list
, &bdata_list
);
63 list_for_each_entry(ent
, &bdata_list
, list
) {
64 if (bdata
->node_boot_start
< ent
->node_boot_start
) {
65 list_add_tail(&bdata
->list
, &ent
->list
);
69 list_add_tail(&bdata
->list
, &bdata_list
);
73 * Given an initialised bdata, it returns the size of the boot bitmap
75 static unsigned long __init
get_mapsize(bootmem_data_t
*bdata
)
77 unsigned long mapsize
;
78 unsigned long start
= PFN_DOWN(bdata
->node_boot_start
);
79 unsigned long end
= bdata
->node_low_pfn
;
81 mapsize
= ((end
- start
) + 7) / 8;
82 return ALIGN(mapsize
, sizeof(long));
86 * Called once to set up the allocator itself.
88 static unsigned long __init
init_bootmem_core(pg_data_t
*pgdat
,
89 unsigned long mapstart
, unsigned long start
, unsigned long end
)
91 bootmem_data_t
*bdata
= pgdat
->bdata
;
92 unsigned long mapsize
;
94 bdata
->node_bootmem_map
= phys_to_virt(PFN_PHYS(mapstart
));
95 bdata
->node_boot_start
= PFN_PHYS(start
);
96 bdata
->node_low_pfn
= end
;
100 * Initially all pages are reserved - setup_arch() has to
101 * register free RAM areas explicitly.
103 mapsize
= get_mapsize(bdata
);
104 memset(bdata
->node_bootmem_map
, 0xff, mapsize
);
110 * Marks a particular physical memory range as unallocatable. Usable RAM
111 * might be used for boot-time allocations - or it might get added
112 * to the free page pool later on.
114 static int __init
reserve_bootmem_core(bootmem_data_t
*bdata
,
115 unsigned long addr
, unsigned long size
, int flags
)
117 unsigned long sidx
, eidx
;
122 * round up, partially reserved pages are considered
126 BUG_ON(PFN_DOWN(addr
) >= bdata
->node_low_pfn
);
127 BUG_ON(PFN_UP(addr
+ size
) > bdata
->node_low_pfn
);
128 BUG_ON(addr
< bdata
->node_boot_start
);
130 sidx
= PFN_DOWN(addr
- bdata
->node_boot_start
);
131 eidx
= PFN_UP(addr
+ size
- bdata
->node_boot_start
);
133 for (i
= sidx
; i
< eidx
; i
++)
134 if (test_and_set_bit(i
, bdata
->node_bootmem_map
)) {
135 #ifdef CONFIG_DEBUG_BOOTMEM
136 printk("hm, page %08lx reserved twice.\n", i
*PAGE_SIZE
);
138 if (flags
& BOOTMEM_EXCLUSIVE
) {
147 /* unreserve memory we accidentally reserved */
148 for (i
--; i
>= sidx
; i
--)
149 clear_bit(i
, bdata
->node_bootmem_map
);
154 static void __init
free_bootmem_core(bootmem_data_t
*bdata
, unsigned long addr
,
157 unsigned long sidx
, eidx
;
163 if (addr
+ size
< bdata
->node_boot_start
||
164 PFN_DOWN(addr
) > bdata
->node_low_pfn
)
167 * round down end of usable mem, partially free pages are
168 * considered reserved.
171 if (addr
>= bdata
->node_boot_start
&& addr
< bdata
->last_success
)
172 bdata
->last_success
= addr
;
175 * Round up to index to the range.
177 if (PFN_UP(addr
) > PFN_DOWN(bdata
->node_boot_start
))
178 sidx
= PFN_UP(addr
) - PFN_DOWN(bdata
->node_boot_start
);
182 eidx
= PFN_DOWN(addr
+ size
- bdata
->node_boot_start
);
183 if (eidx
> bdata
->node_low_pfn
- PFN_DOWN(bdata
->node_boot_start
))
184 eidx
= bdata
->node_low_pfn
- PFN_DOWN(bdata
->node_boot_start
);
186 for (i
= sidx
; i
< eidx
; i
++) {
187 if (unlikely(!test_and_clear_bit(i
, bdata
->node_bootmem_map
)))
193 * We 'merge' subsequent allocations to save space. We might 'lose'
194 * some fraction of a page if allocations cannot be satisfied due to
195 * size constraints on boxes where there is physical RAM space
196 * fragmentation - in these cases (mostly large memory boxes) this
199 * On low memory boxes we get it right in 100% of the cases.
201 * alignment has to be a power of 2 value.
203 * NOTE: This function is _not_ reentrant.
206 __alloc_bootmem_core(struct bootmem_data
*bdata
, unsigned long size
,
207 unsigned long align
, unsigned long goal
, unsigned long limit
)
209 unsigned long offset
, remaining_size
, areasize
, preferred
;
210 unsigned long i
, start
= 0, incr
, eidx
, end_pfn
;
214 printk("__alloc_bootmem_core(): zero-sized request\n");
217 BUG_ON(align
& (align
-1));
219 if (limit
&& bdata
->node_boot_start
>= limit
)
222 /* on nodes without memory - bootmem_map is NULL */
223 if (!bdata
->node_bootmem_map
)
226 end_pfn
= bdata
->node_low_pfn
;
227 limit
= PFN_DOWN(limit
);
228 if (limit
&& end_pfn
> limit
)
231 eidx
= end_pfn
- PFN_DOWN(bdata
->node_boot_start
);
233 if (align
&& (bdata
->node_boot_start
& (align
- 1UL)) != 0)
234 offset
= align
- (bdata
->node_boot_start
& (align
- 1UL));
235 offset
= PFN_DOWN(offset
);
238 * We try to allocate bootmem pages above 'goal'
239 * first, then we try to allocate lower pages.
242 if (goal
&& PFN_DOWN(goal
) < end_pfn
) {
243 if (goal
> bdata
->node_boot_start
)
244 preferred
= goal
- bdata
->node_boot_start
;
246 if (bdata
->last_success
>= preferred
)
247 if (!limit
|| (limit
&& limit
> bdata
->last_success
))
248 preferred
= bdata
->last_success
;
251 preferred
= PFN_DOWN(ALIGN(preferred
, align
)) + offset
;
252 areasize
= (size
+ PAGE_SIZE
-1) / PAGE_SIZE
;
253 incr
= align
>> PAGE_SHIFT
? : 1;
256 for (i
= preferred
; i
< eidx
;) {
259 i
= find_next_zero_bit(bdata
->node_bootmem_map
, eidx
, i
);
263 if (test_bit(i
, bdata
->node_bootmem_map
)) {
267 for (j
= i
+ 1; j
< i
+ areasize
; ++j
) {
270 if (test_bit(j
, bdata
->node_bootmem_map
))
281 if (preferred
> offset
) {
288 bdata
->last_success
= PFN_PHYS(start
);
289 BUG_ON(start
>= eidx
);
292 * Is the next page of the previous allocation-end the start
293 * of this allocation's buffer? If yes then we can 'merge'
294 * the previous partial page with this allocation.
296 if (align
< PAGE_SIZE
&&
297 bdata
->last_offset
&& bdata
->last_pos
+1 == start
) {
298 offset
= ALIGN(bdata
->last_offset
, align
);
299 BUG_ON(offset
> PAGE_SIZE
);
300 remaining_size
= PAGE_SIZE
- offset
;
301 if (size
< remaining_size
) {
303 /* last_pos unchanged */
304 bdata
->last_offset
= offset
+ size
;
305 ret
= phys_to_virt(bdata
->last_pos
* PAGE_SIZE
+
307 bdata
->node_boot_start
);
309 remaining_size
= size
- remaining_size
;
310 areasize
= (remaining_size
+ PAGE_SIZE
-1) / PAGE_SIZE
;
311 ret
= phys_to_virt(bdata
->last_pos
* PAGE_SIZE
+
313 bdata
->node_boot_start
);
314 bdata
->last_pos
= start
+ areasize
- 1;
315 bdata
->last_offset
= remaining_size
;
317 bdata
->last_offset
&= ~PAGE_MASK
;
319 bdata
->last_pos
= start
+ areasize
- 1;
320 bdata
->last_offset
= size
& ~PAGE_MASK
;
321 ret
= phys_to_virt(start
* PAGE_SIZE
+ bdata
->node_boot_start
);
325 * Reserve the area now:
327 for (i
= start
; i
< start
+ areasize
; i
++)
328 if (unlikely(test_and_set_bit(i
, bdata
->node_bootmem_map
)))
330 memset(ret
, 0, size
);
334 static unsigned long __init
free_all_bootmem_core(pg_data_t
*pgdat
)
338 bootmem_data_t
*bdata
= pgdat
->bdata
;
339 unsigned long i
, count
, total
= 0;
344 BUG_ON(!bdata
->node_bootmem_map
);
347 /* first extant page of the node */
348 pfn
= PFN_DOWN(bdata
->node_boot_start
);
349 idx
= bdata
->node_low_pfn
- pfn
;
350 map
= bdata
->node_bootmem_map
;
351 /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
352 if (bdata
->node_boot_start
== 0 ||
353 ffs(bdata
->node_boot_start
) - PAGE_SHIFT
> ffs(BITS_PER_LONG
))
355 for (i
= 0; i
< idx
; ) {
356 unsigned long v
= ~map
[i
/ BITS_PER_LONG
];
358 if (gofast
&& v
== ~0UL) {
361 page
= pfn_to_page(pfn
);
362 count
+= BITS_PER_LONG
;
363 order
= ffs(BITS_PER_LONG
) - 1;
364 __free_pages_bootmem(page
, order
);
366 page
+= BITS_PER_LONG
;
370 page
= pfn_to_page(pfn
);
371 for (m
= 1; m
&& i
< idx
; m
<<=1, page
++, i
++) {
374 __free_pages_bootmem(page
, 0);
380 pfn
+= BITS_PER_LONG
;
385 * Now free the allocator bitmap itself, it's not
388 page
= virt_to_page(bdata
->node_bootmem_map
);
390 idx
= (get_mapsize(bdata
) + PAGE_SIZE
-1) >> PAGE_SHIFT
;
391 for (i
= 0; i
< idx
; i
++, page
++) {
392 __free_pages_bootmem(page
, 0);
396 bdata
->node_bootmem_map
= NULL
;
401 unsigned long __init
init_bootmem_node(pg_data_t
*pgdat
, unsigned long freepfn
,
402 unsigned long startpfn
, unsigned long endpfn
)
404 return init_bootmem_core(pgdat
, freepfn
, startpfn
, endpfn
);
407 void __init
reserve_bootmem_node(pg_data_t
*pgdat
, unsigned long physaddr
,
408 unsigned long size
, int flags
)
410 reserve_bootmem_core(pgdat
->bdata
, physaddr
, size
, flags
);
413 void __init
free_bootmem_node(pg_data_t
*pgdat
, unsigned long physaddr
,
416 free_bootmem_core(pgdat
->bdata
, physaddr
, size
);
419 unsigned long __init
free_all_bootmem_node(pg_data_t
*pgdat
)
421 return free_all_bootmem_core(pgdat
);
424 unsigned long __init
init_bootmem(unsigned long start
, unsigned long pages
)
428 return init_bootmem_core(NODE_DATA(0), start
, 0, pages
);
431 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
432 int __init
reserve_bootmem(unsigned long addr
, unsigned long size
,
435 return reserve_bootmem_core(NODE_DATA(0)->bdata
, addr
, size
, flags
);
437 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
439 void __init
free_bootmem(unsigned long addr
, unsigned long size
)
441 bootmem_data_t
*bdata
;
442 list_for_each_entry(bdata
, &bdata_list
, list
)
443 free_bootmem_core(bdata
, addr
, size
);
446 unsigned long __init
free_all_bootmem(void)
448 return free_all_bootmem_core(NODE_DATA(0));
451 void * __init
__alloc_bootmem_nopanic(unsigned long size
, unsigned long align
,
454 bootmem_data_t
*bdata
;
457 list_for_each_entry(bdata
, &bdata_list
, list
) {
458 ptr
= __alloc_bootmem_core(bdata
, size
, align
, goal
, 0);
465 void * __init
__alloc_bootmem(unsigned long size
, unsigned long align
,
468 void *mem
= __alloc_bootmem_nopanic(size
,align
,goal
);
473 * Whoops, we cannot satisfy the allocation request.
475 printk(KERN_ALERT
"bootmem alloc of %lu bytes failed!\n", size
);
476 panic("Out of memory");
481 void * __init
__alloc_bootmem_node(pg_data_t
*pgdat
, unsigned long size
,
482 unsigned long align
, unsigned long goal
)
486 ptr
= __alloc_bootmem_core(pgdat
->bdata
, size
, align
, goal
, 0);
490 return __alloc_bootmem(size
, align
, goal
);
493 #ifndef ARCH_LOW_ADDRESS_LIMIT
494 #define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
497 void * __init
__alloc_bootmem_low(unsigned long size
, unsigned long align
,
500 bootmem_data_t
*bdata
;
503 list_for_each_entry(bdata
, &bdata_list
, list
) {
504 ptr
= __alloc_bootmem_core(bdata
, size
, align
, goal
,
505 ARCH_LOW_ADDRESS_LIMIT
);
511 * Whoops, we cannot satisfy the allocation request.
513 printk(KERN_ALERT
"low bootmem alloc of %lu bytes failed!\n", size
);
514 panic("Out of low memory");
518 void * __init
__alloc_bootmem_low_node(pg_data_t
*pgdat
, unsigned long size
,
519 unsigned long align
, unsigned long goal
)
521 return __alloc_bootmem_core(pgdat
->bdata
, size
, align
, goal
,
522 ARCH_LOW_ADDRESS_LIMIT
);
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