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;
51 pgdat->pgdat_next = pgdat_list;
54 mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
55 bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
56 bdata->node_boot_start = (start << PAGE_SHIFT);
57 bdata->node_low_pfn = end;
60 * Initially all pages are reserved - setup_arch() has to
61 * register free RAM areas explicitly.
63 memset(bdata->node_bootmem_map, 0xff, mapsize);
69 * Marks a particular physical memory range as unallocatable. Usable RAM
70 * might be used for boot-time allocations - or it might get added
71 * to the free page pool later on.
73 static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
77 * round up, partially reserved pages are considered
80 unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
81 unsigned long eidx = (addr + size - bdata->node_boot_start +
82 PAGE_SIZE-1)/PAGE_SIZE;
83 unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
87 BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
88 BUG_ON(end > bdata->node_low_pfn);
90 for (i = sidx; i < eidx; i++)
91 if (test_and_set_bit(i, bdata->node_bootmem_map)) {
92 #ifdef CONFIG_DEBUG_BOOTMEM
93 printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
98 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
103 * round down end of usable mem, partially free pages are
104 * considered reserved.
107 unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
108 unsigned long end = (addr + size)/PAGE_SIZE;
111 BUG_ON(end > bdata->node_low_pfn);
113 if (addr < bdata->last_success)
114 bdata->last_success = addr;
117 * Round up the beginning of the address.
119 start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
120 sidx = start - (bdata->node_boot_start/PAGE_SIZE);
122 for (i = sidx; i < eidx; i++) {
123 if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
129 * We 'merge' subsequent allocations to save space. We might 'lose'
130 * some fraction of a page if allocations cannot be satisfied due to
131 * size constraints on boxes where there is physical RAM space
132 * fragmentation - in these cases (mostly large memory boxes) this
135 * On low memory boxes we get it right in 100% of the cases.
137 * alignment has to be a power of 2 value.
139 * NOTE: This function is _not_ reentrant.
142 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
143 unsigned long align, unsigned long goal)
145 unsigned long offset, remaining_size, areasize, preferred;
146 unsigned long i, start = 0, incr, eidx;
150 printk("__alloc_bootmem_core(): zero-sized request\n");
153 BUG_ON(align & (align-1));
155 eidx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
158 (bdata->node_boot_start & (align - 1UL)) != 0)
159 offset = (align - (bdata->node_boot_start & (align - 1UL)));
160 offset >>= PAGE_SHIFT;
163 * We try to allocate bootmem pages above 'goal'
164 * first, then we try to allocate lower pages.
166 if (goal && (goal >= bdata->node_boot_start) &&
167 ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
168 preferred = goal - bdata->node_boot_start;
170 if (bdata->last_success >= preferred)
171 preferred = bdata->last_success;
175 preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
177 areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
178 incr = align >> PAGE_SHIFT ? : 1;
181 for (i = preferred; i < eidx; i += incr) {
183 i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
185 if (test_bit(i, bdata->node_bootmem_map))
187 for (j = i + 1; j < i + areasize; ++j) {
190 if (test_bit (j, bdata->node_bootmem_map))
199 if (preferred > offset) {
206 bdata->last_success = start << PAGE_SHIFT;
207 BUG_ON(start >= eidx);
210 * Is the next page of the previous allocation-end the start
211 * of this allocation's buffer? If yes then we can 'merge'
212 * the previous partial page with this allocation.
214 if (align < PAGE_SIZE &&
215 bdata->last_offset && bdata->last_pos+1 == start) {
216 offset = (bdata->last_offset+align-1) & ~(align-1);
217 BUG_ON(offset > PAGE_SIZE);
218 remaining_size = PAGE_SIZE-offset;
219 if (size < remaining_size) {
221 /* last_pos unchanged */
222 bdata->last_offset = offset+size;
223 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
224 bdata->node_boot_start);
226 remaining_size = size - remaining_size;
227 areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
228 ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
229 bdata->node_boot_start);
230 bdata->last_pos = start+areasize-1;
231 bdata->last_offset = remaining_size;
233 bdata->last_offset &= ~PAGE_MASK;
235 bdata->last_pos = start + areasize - 1;
236 bdata->last_offset = size & ~PAGE_MASK;
237 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
241 * Reserve the area now:
243 for (i = start; i < start+areasize; i++)
244 if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
246 memset(ret, 0, size);
250 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
253 bootmem_data_t *bdata = pgdat->bdata;
254 unsigned long i, count, total = 0;
258 BUG_ON(!bdata->node_bootmem_map);
261 /* first extant page of the node */
262 page = virt_to_page(phys_to_virt(bdata->node_boot_start));
263 idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
264 map = bdata->node_bootmem_map;
265 for (i = 0; i < idx; ) {
266 unsigned long v = ~map[i / BITS_PER_LONG];
269 for (m = 1; m && i < idx; m<<=1, page++, i++) {
272 ClearPageReserved(page);
273 set_page_count(page, 1);
279 page += BITS_PER_LONG;
285 * Now free the allocator bitmap itself, it's not
288 page = virt_to_page(bdata->node_bootmem_map);
290 for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
292 ClearPageReserved(page);
293 set_page_count(page, 1);
297 bdata->node_bootmem_map = NULL;
302 unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
304 return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
307 void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
309 reserve_bootmem_core(pgdat->bdata, physaddr, size);
312 void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
314 free_bootmem_core(pgdat->bdata, physaddr, size);
317 unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
319 return(free_all_bootmem_core(pgdat));
322 #ifndef CONFIG_DISCONTIGMEM
323 unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
327 return(init_bootmem_core(&contig_page_data, start, 0, pages));
330 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
331 void __init reserve_bootmem (unsigned long addr, unsigned long size)
333 reserve_bootmem_core(contig_page_data.bdata, addr, size);
335 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
337 void __init free_bootmem (unsigned long addr, unsigned long size)
339 free_bootmem_core(contig_page_data.bdata, addr, size);
342 unsigned long __init free_all_bootmem (void)
344 return(free_all_bootmem_core(&contig_page_data));
346 #endif /* !CONFIG_DISCONTIGMEM */
348 void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
350 pg_data_t *pgdat = pgdat_list;
353 for_each_pgdat(pgdat)
354 if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
359 * Whoops, we cannot satisfy the allocation request.
361 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
362 panic("Out of memory");
366 void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal)
370 ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal);
375 * Whoops, we cannot satisfy the allocation request.
377 printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
378 panic("Out of memory");