mm/bootmem.c

   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 <asm/dma.h>
  20 #include <asm/io.h>
  21
  22 /*
  23  * Access to this subsystem has to be serialized externally. (this is
  24  * true for the boot process anyway)
  25  */
  26 unsigned long max_low_pfn;
  27 unsigned long min_low_pfn;
  28 unsigned long max_pfn;
  29
  30 /* return the number of _pages_ that will be allocated for the boot bitmap */
  31 unsigned long __init bootmem_bootmap_pages (unsigned long pages)
  32 {
  33         unsigned long mapsize;
  34
  35         mapsize = (pages+7)/8;
  36         mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
  37         mapsize >>= PAGE_SHIFT;
  38
  39         return mapsize;
  40 }
  41
  42 /*
  43  * Called once to set up the allocator itself.
  44  */
  45 static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
  46         unsigned long mapstart, unsigned long start, unsigned long end)
  47 {
  48         bootmem_data_t *bdata = pgdat->bdata;
  49         unsigned long mapsize = ((end - start)+7)/8;
  50
  51         pgdat->pgdat_next = pgdat_list;
  52         pgdat_list = pgdat;
  53
  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;
  58
  59         /*
  60          * Initially all pages are reserved - setup_arch() has to
  61          * register free RAM areas explicitly.
  62          */
  63         memset(bdata->node_bootmem_map, 0xff, mapsize);
  64
  65         return mapsize;
  66 }
  67
  68 /*
  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.
  72  */
  73 static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
  74 {
  75         unsigned long i;
  76         /*
  77          * round up, partially reserved pages are considered
  78          * fully reserved.
  79          */
  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;
  84
  85         if (!size) BUG();
  86
  87         if (sidx < 0)
  88                 BUG();
  89         if (eidx < 0)
  90                 BUG();
  91         if (sidx >= eidx)
  92                 BUG();
  93         if ((addr >> PAGE_SHIFT) >= bdata->node_low_pfn)
  94                 BUG();
  95         if (end > bdata->node_low_pfn)
  96                 BUG();
  97         for (i = sidx; i < eidx; i++)
  98                 if (test_and_set_bit(i, bdata->node_bootmem_map))
  99                         printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
 100 }
 101
 102 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
 103 {
 104         unsigned long i;
 105         unsigned long start;
 106         /*
 107          * round down end of usable mem, partially free pages are
 108          * considered reserved.
 109          */
 110         unsigned long sidx;
 111         unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
 112         unsigned long end = (addr + size)/PAGE_SIZE;
 113
 114         if (!size) BUG();
 115         if (end > bdata->node_low_pfn)
 116                 BUG();
 117
 118         /*
 119          * Round up the beginning of the address.
 120          */
 121         start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
 122         sidx = start - (bdata->node_boot_start/PAGE_SIZE);
 123
 124         for (i = sidx; i < eidx; i++) {
 125                 if (!test_and_clear_bit(i, bdata->node_bootmem_map))
 126                         BUG();
 127         }
 128 }
 129
 130 /*
 131  * We 'merge' subsequent allocations to save space. We might 'lose'
 132  * some fraction of a page if allocations cannot be satisfied due to
 133  * size constraints on boxes where there is physical RAM space
 134  * fragmentation - in these cases * (mostly large memory boxes) this
 135  * is not a problem.
 136  *
 137  * On low memory boxes we get it right in 100% of the cases.
 138  */
 139
 140 /*
 141  * alignment has to be a power of 2 value.
 142  */
 143 static void * __init __alloc_bootmem_core (bootmem_data_t *bdata,
 144         unsigned long size, unsigned long align, unsigned long goal)
 145 {
 146         unsigned long i, start = 0;
 147         void *ret;
 148         unsigned long offset, remaining_size;
 149         unsigned long areasize, preferred, incr;
 150         unsigned long eidx = bdata->node_low_pfn - (bdata->node_boot_start >>
 151                                                         PAGE_SHIFT);
 152
 153         if (!size) BUG();
 154
 155         if (align & (align-1))
 156                 BUG();
 157
 158         offset = 0;
 159         if (align &&
 160             (bdata->node_boot_start & (align - 1UL)) != 0)
 161                 offset = (align - (bdata->node_boot_start & (align - 1UL)));
 162         offset >>= PAGE_SHIFT;
 163
 164         /*
 165          * We try to allocate bootmem pages above 'goal'
 166          * first, then we try to allocate lower pages.
 167          */
 168         if (goal && (goal >= bdata->node_boot_start) &&
 169                         ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) {
 170                 preferred = goal - bdata->node_boot_start;
 171         } else
 172                 preferred = 0;
 173
 174         preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
 175         preferred += offset;
 176         areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
 177         incr = align >> PAGE_SHIFT ? : 1;
 178
 179 restart_scan:
 180         for (i = preferred; i < eidx; i += incr) {
 181                 unsigned long j;
 182                 if (test_bit(i, bdata->node_bootmem_map))
 183                         continue;
 184                 for (j = i + 1; j < i + areasize; ++j) {
 185                         if (j >= eidx)
 186                                 goto fail_block;
 187                         if (test_bit (j, bdata->node_bootmem_map))
 188                                 goto fail_block;
 189                 }
 190                 start = i;
 191                 goto found;
 192         fail_block:;
 193         }
 194         if (preferred) {
 195                 preferred = offset;
 196                 goto restart_scan;
 197         }
 198         return NULL;
 199 found:
 200         if (start >= eidx)
 201                 BUG();
 202
 203         /*
 204          * Is the next page of the previous allocation-end the start
 205          * of this allocation's buffer? If yes then we can 'merge'
 206          * the previous partial page with this allocation.
 207          */
 208         if (align < PAGE_SIZE
 209             && bdata->last_offset && bdata->last_pos+1 == start) {
 210                 offset = (bdata->last_offset+align-1) & ~(align-1);
 211                 if (offset > PAGE_SIZE)
 212                         BUG();
 213                 remaining_size = PAGE_SIZE-offset;
 214                 if (size < remaining_size) {
 215                         areasize = 0;
 216                         // last_pos unchanged
 217                         bdata->last_offset = offset+size;
 218                         ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
 219                                                 bdata->node_boot_start);
 220                 } else {
 221                         remaining_size = size - remaining_size;
 222                         areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
 223                         ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
 224                                                 bdata->node_boot_start);
 225                         bdata->last_pos = start+areasize-1;
 226                         bdata->last_offset = remaining_size;
 227                 }
 228                 bdata->last_offset &= ~PAGE_MASK;
 229         } else {
 230                 bdata->last_pos = start + areasize - 1;
 231                 bdata->last_offset = size & ~PAGE_MASK;
 232                 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
 233         }
 234         /*
 235          * Reserve the area now:
 236          */
 237         for (i = start; i < start+areasize; i++)
 238                 if (test_and_set_bit(i, bdata->node_bootmem_map))
 239                         BUG();
 240         memset(ret, 0, size);
 241         return ret;
 242 }
 243
 244 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
 245 {
 246         struct page *page = pgdat->node_mem_map;
 247         bootmem_data_t *bdata = pgdat->bdata;
 248         unsigned long i, count, total = 0;
 249         unsigned long idx;
 250         unsigned long *map;
 251
 252         if (!bdata->node_bootmem_map) BUG();
 253
 254         count = 0;
 255         idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
 256         map = bdata->node_bootmem_map;
 257         for (i = 0; i < idx; ) {
 258                 unsigned long v = ~map[i / BITS_PER_LONG];
 259                 if (v) {
 260                         unsigned long m;
 261                         for (m = 1; m && i < idx; m<<=1, page++, i++) {
 262                                 if (v & m) {
 263                         count++;
 264                         ClearPageReserved(page);
 265                         set_page_count(page, 1);
 266                         __free_page(page);
 267                 }
 268         }
 269                 } else {
 270                         i+=BITS_PER_LONG;
 271                         page+=BITS_PER_LONG;
 272                 }
 273         }
 274         total += count;
 275
 276         /*
 277          * Now free the allocator bitmap itself, it's not
 278          * needed anymore:
 279          */
 280         page = virt_to_page(bdata->node_bootmem_map);
 281         count = 0;
 282         for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
 283                 count++;
 284                 ClearPageReserved(page);
 285                 set_page_count(page, 1);
 286                 __free_page(page);
 287         }
 288         total += count;
 289         bdata->node_bootmem_map = NULL;
 290
 291         return total;
 292 }
 293
 294 unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
 295 {
 296         return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
 297 }
 298
 299 void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
 300 {
 301         reserve_bootmem_core(pgdat->bdata, physaddr, size);
 302 }
 303
 304 void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
 305 {
 306         return(free_bootmem_core(pgdat->bdata, physaddr, size));
 307 }
 308
 309 unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
 310 {
 311         return(free_all_bootmem_core(pgdat));
 312 }
 313
 314 #ifndef CONFIG_DISCONTIGMEM
 315 unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
 316 {
 317         max_low_pfn = pages;
 318         min_low_pfn = start;
 319         return(init_bootmem_core(&contig_page_data, start, 0, pages));
 320 }
 321
 322 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
 323 void __init reserve_bootmem (unsigned long addr, unsigned long size)
 324 {
 325         reserve_bootmem_core(contig_page_data.bdata, addr, size);
 326 }
 327 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
 328
 329 void __init free_bootmem (unsigned long addr, unsigned long size)
 330 {
 331         return(free_bootmem_core(contig_page_data.bdata, addr, size));
 332 }
 333
 334 unsigned long __init free_all_bootmem (void)
 335 {
 336         return(free_all_bootmem_core(&contig_page_data));
 337 }
 338 #endif /* !CONFIG_DISCONTIGMEM */
 339
 340 void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal)
 341 {
 342         pg_data_t *pgdat = pgdat_list;
 343         void *ptr;
 344
 345         for_each_pgdat(pgdat)
 346                 if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
 347                                                 align, goal)))
 348                         return(ptr);
 349
 350         /*
 351          * Whoops, we cannot satisfy the allocation request.
 352          */
 353         printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
 354         panic("Out of memory");
 355         return NULL;
 356 }
 357
 358 void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal)
 359 {
 360         void *ptr;
 361
 362         ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal);
 363         if (ptr)
 364                 return (ptr);
 365
 366         /*
 367          * Whoops, we cannot satisfy the allocation request.
 368          */
 369         printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
 370         panic("Out of memory");
 371         return NULL;
 372 }
 373