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.
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>
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 /* return the number of _pages_ that will be allocated for the boot bitmap */
31 unsigned long __init bootmem_bootmap_pages (unsigned long pages)
33 unsigned long mapsize;
35 mapsize = (pages+7)/8;
36 mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
37 mapsize >>= PAGE_SHIFT;
43 * Called once to set up the allocator itself.
45 static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
46 unsigned long mapstart, unsigned long start, unsigned long end)
48 bootmem_data_t *bdata = pgdat->bdata;
49 unsigned long mapsize = ((end - start)+7)/8;
53 * sort pgdat_list so that the lowest one comes first,
54 * which makes alloc_bootmem_low_pages work as desired.
56 if (!pgdat_list || pgdat_list->node_start_pfn > pgdat->node_start_pfn) {
57 pgdat->pgdat_next = pgdat_list;
60 pg_data_t *tmp = pgdat_list;
61 while (tmp->pgdat_next) {
62 if (tmp->pgdat_next->node_start_pfn > pgdat->node_start_pfn)
64 tmp = tmp->pgdat_next;
66 pgdat->pgdat_next = tmp->pgdat_next;
67 tmp->pgdat_next = pgdat;
70 mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
71 bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
72 bdata->node_boot_start = (start << PAGE_SHIFT);
73 bdata->node_low_pfn = end;
76 * Initially all pages are reserved - setup_arch() has to
77 * register free RAM areas explicitly.
79 memset(bdata->node_bootmem_map, 0xff, mapsize);
85 * Marks a particular physical memory range as unallocatable. Usable RAM
86 * might be used for boot-time allocations - or it might get added
87 * to the free page pool later on.
89 static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
93 * round up, partially reserved pages are considered
96 unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
97 unsigned long eidx = (addr + size - bdata->node_boot_start +
98 PAGE_SIZE-1)/PAGE_SIZE;
99 unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
105 if ((addr >> PAGE_SHIFT) >= bdata->node_low_pfn)
107 if (end > bdata->node_low_pfn)
109 for (i = sidx; i < eidx; i++)
110 if (test_and_set_bit(i, bdata->node_bootmem_map))
111 printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
114 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
119 * round down end of usable mem, partially free pages are
120 * considered reserved.
123 unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
124 unsigned long end = (addr + size)/PAGE_SIZE;
127 if (end > bdata->node_low_pfn)
130 if (addr < bdata->last_success)
131 bdata->last_success = addr;
134 * Round up the beginning of the address.
136 start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
137 sidx = start - (bdata->node_boot_start/PAGE_SIZE);
139 for (i = sidx; i < eidx; i++) {
140 if (!test_and_clear_bit(i, bdata->node_bootmem_map))
146 * We 'merge' subsequent allocations to save space. We might 'lose'
147 * some fraction of a page if allocations cannot be satisfied due to
148 * size constraints on boxes where there is physical RAM space
149 * fragmentation - in these cases * (mostly large memory boxes) this
152 * On low memory boxes we get it right in 100% of the cases.
154 * alignment has to be a power of 2 value.
156 * NOTE: This function is _not_ reenetrant.
159 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
160 unsigned long align, unsigned long goal)
162 unsigned long offset, remaining_size, areasize, preferred;
163 unsigned long i, start = 0, incr, eidx;
167 printk("__alloc_bootmem_core(): zero-sized request\n");
171 BUG_ON(align & (align-1));
173 eidx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
176 (bdata->node_boot_start & (align - 1UL)) != 0)
177 offset = (align - (bdata->node_boot_start & (align - 1UL)));
178 offset >>= PAGE_SHIFT;
181 * We try to allocate bootmem pages above 'goal'
182 * first, then we try to allocate lower pages.
184 if (goal && (goal >= bdata->node_boot_start) &&
185 ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
186 preferred = goal - bdata->node_boot_start;
188 if (bdata->last_success >= preferred)
189 preferred = bdata->last_success;
193 preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
195 areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
196 incr = align >> PAGE_SHIFT ? : 1;
199 for (i = preferred; i < eidx; i += incr) {
201 i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
203 if (test_bit(i, bdata->node_bootmem_map))
205 for (j = i + 1; j < i + areasize; ++j) {
208 if (test_bit (j, bdata->node_bootmem_map))
217 if (preferred > offset) {
224 bdata->last_success = start << PAGE_SHIFT;
225 BUG_ON(start >= eidx);
228 * Is the next page of the previous allocation-end the start
229 * of this allocation's buffer? If yes then we can 'merge'
230 * the previous partial page with this allocation.
232 if (align < PAGE_SIZE &&
233 bdata->last_offset && bdata->last_pos+1 == start) {
234 offset = (bdata->last_offset+align-1) & ~(align-1);
235 BUG_ON(offset > PAGE_SIZE);
236 remaining_size = PAGE_SIZE-offset;
237 if (size < remaining_size) {
239 /* last_pos unchanged */
240 bdata->last_offset = offset+size;
241 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
242 bdata->node_boot_start);
244 remaining_size = size - remaining_size;
245 areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
246 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
247 bdata->node_boot_start);
248 bdata->last_pos = start+areasize-1;
249 bdata->last_offset = remaining_size;
251 bdata->last_offset &= ~PAGE_MASK;
253 bdata->last_pos = start + areasize - 1;
254 bdata->last_offset = size & ~PAGE_MASK;
255 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
259 * Reserve the area now:
261 for (i = start; i < start+areasize; i++)
262 if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
264 memset(ret, 0, size);
268 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
271 bootmem_data_t *bdata = pgdat->bdata;
272 unsigned long i, count, total = 0;
276 if (!bdata->node_bootmem_map) BUG();
279 /* first extant page of the node */
280 page = virt_to_page(phys_to_virt(bdata->node_boot_start));
281 idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
282 map = bdata->node_bootmem_map;
283 for (i = 0; i < idx; ) {
284 unsigned long v = ~map[i / BITS_PER_LONG];
287 for (m = 1; m && i < idx; m<<=1, page++, i++) {
290 ClearPageReserved(page);
291 set_page_count(page, 1);
297 page += BITS_PER_LONG;
303 * Now free the allocator bitmap itself, it's not
306 page = virt_to_page(bdata->node_bootmem_map);
308 for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
310 ClearPageReserved(page);
311 set_page_count(page, 1);
315 bdata->node_bootmem_map = NULL;
320 unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
322 return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
325 void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
327 reserve_bootmem_core(pgdat->bdata, physaddr, size);
330 void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
332 free_bootmem_core(pgdat->bdata, physaddr, size);
335 unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
337 return(free_all_bootmem_core(pgdat));
340 #ifndef CONFIG_DISCONTIGMEM
341 unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
345 return(init_bootmem_core(&contig_page_data, start, 0, pages));
348 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
349 void __init reserve_bootmem (unsigned long addr, unsigned long size)
351 reserve_bootmem_core(contig_page_data.bdata, addr, size);
353 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
355 void __init free_bootmem (unsigned long addr, unsigned long size)
357 free_bootmem_core(contig_page_data.bdata, addr, size);
360 unsigned long __init free_all_bootmem (void)
362 return(free_all_bootmem_core(&contig_page_data));
364 #endif /* !CONFIG_DISCONTIGMEM */
366 void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
368 pg_data_t *pgdat = pgdat_list;
371 for_each_pgdat(pgdat)
372 if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
377 * Whoops, we cannot satisfy the allocation request.
379 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
380 panic("Out of memory");
384 void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal)
388 ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal);
393 * Whoops, we cannot satisfy the allocation request.
395 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
396 panic("Out of memory");