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 <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  */
  28 unsigned long max_low_pfn;
  29 unsigned long min_low_pfn;
  30 unsigned long max_pfn;
  31
  32 EXPORT_UNUSED_SYMBOL(max_pfn);  /*  June 2006  */
  33
  34 static LIST_HEAD(bdata_list);
  35 #ifdef CONFIG_CRASH_DUMP
  36 /*
  37  * If we have booted due to a crash, max_pfn will be a very low value. We need
  38  * to know the amount of memory that the previous kernel used.
  39  */
  40 unsigned long saved_max_pfn;
  41 #endif
  42
  43 /* return the number of _pages_ that will be allocated for the boot bitmap */
  44 unsigned long __init bootmem_bootmap_pages (unsigned long pages)
  45 {
  46         unsigned long mapsize;
  47
  48         mapsize = (pages+7)/8;
  49         mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
  50         mapsize >>= PAGE_SHIFT;
  51
  52         return mapsize;
  53 }
  54 /*
  55  * link bdata in order
  56  */
  57 static void link_bootmem(bootmem_data_t *bdata)
  58 {
  59         bootmem_data_t *ent;
  60         if (list_empty(&bdata_list)) {
  61                 list_add(&bdata->list, &bdata_list);
  62                 return;
  63         }
  64         /* insert in order */
  65         list_for_each_entry(ent, &bdata_list, list) {
  66                 if (bdata->node_boot_start < ent->node_boot_start) {
  67                         list_add_tail(&bdata->list, &ent->list);
  68                         return;
  69                 }
  70         }
  71         list_add_tail(&bdata->list, &bdata_list);
  72         return;
  73 }
  74
  75
  76 /*
  77  * Called once to set up the allocator itself.
  78  */
  79 static unsigned long __init init_bootmem_core (pg_data_t *pgdat,
  80         unsigned long mapstart, unsigned long start, unsigned long end)
  81 {
  82         bootmem_data_t *bdata = pgdat->bdata;
  83         unsigned long mapsize = ((end - start)+7)/8;
  84
  85         mapsize = ALIGN(mapsize, sizeof(long));
  86         bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
  87         bdata->node_boot_start = (start << PAGE_SHIFT);
  88         bdata->node_low_pfn = end;
  89         link_bootmem(bdata);
  90
  91         /*
  92          * Initially all pages are reserved - setup_arch() has to
  93          * register free RAM areas explicitly.
  94          */
  95         memset(bdata->node_bootmem_map, 0xff, mapsize);
  96
  97         return mapsize;
  98 }
  99
 100 /*
 101  * Marks a particular physical memory range as unallocatable. Usable RAM
 102  * might be used for boot-time allocations - or it might get added
 103  * to the free page pool later on.
 104  */
 105 static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
 106 {
 107         unsigned long i;
 108         /*
 109          * round up, partially reserved pages are considered
 110          * fully reserved.
 111          */
 112         unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
 113         unsigned long eidx = (addr + size - bdata->node_boot_start +
 114                                                         PAGE_SIZE-1)/PAGE_SIZE;
 115         unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;
 116
 117         BUG_ON(!size);
 118         BUG_ON(sidx >= eidx);
 119         BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);
 120         BUG_ON(end > bdata->node_low_pfn);
 121
 122         for (i = sidx; i < eidx; i++)
 123                 if (test_and_set_bit(i, bdata->node_bootmem_map)) {
 124 #ifdef CONFIG_DEBUG_BOOTMEM
 125                         printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
 126 #endif
 127                 }
 128 }
 129
 130 static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size)
 131 {
 132         unsigned long i;
 133         unsigned long start;
 134         /*
 135          * round down end of usable mem, partially free pages are
 136          * considered reserved.
 137          */
 138         unsigned long sidx;
 139         unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;
 140         unsigned long end = (addr + size)/PAGE_SIZE;
 141
 142         BUG_ON(!size);
 143         BUG_ON(end > bdata->node_low_pfn);
 144
 145         if (addr < bdata->last_success)
 146                 bdata->last_success = addr;
 147
 148         /*
 149          * Round up the beginning of the address.
 150          */
 151         start = (addr + PAGE_SIZE-1) / PAGE_SIZE;
 152         sidx = start - (bdata->node_boot_start/PAGE_SIZE);
 153
 154         for (i = sidx; i < eidx; i++) {
 155                 if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
 156                         BUG();
 157         }
 158 }
 159
 160 /*
 161  * We 'merge' subsequent allocations to save space. We might 'lose'
 162  * some fraction of a page if allocations cannot be satisfied due to
 163  * size constraints on boxes where there is physical RAM space
 164  * fragmentation - in these cases (mostly large memory boxes) this
 165  * is not a problem.
 166  *
 167  * On low memory boxes we get it right in 100% of the cases.
 168  *
 169  * alignment has to be a power of 2 value.
 170  *
 171  * NOTE:  This function is _not_ reentrant.
 172  */
 173 void * __init
 174 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
 175               unsigned long align, unsigned long goal, unsigned long limit)
 176 {
 177         unsigned long offset, remaining_size, areasize, preferred;
 178         unsigned long i, start = 0, incr, eidx, end_pfn = bdata->node_low_pfn;
 179         void *ret;
 180
 181         if(!size) {
 182                 printk("__alloc_bootmem_core(): zero-sized request\n");
 183                 BUG();
 184         }
 185         BUG_ON(align & (align-1));
 186
 187         if (limit && bdata->node_boot_start >= limit)
 188                 return NULL;
 189
 190         limit >>=PAGE_SHIFT;
 191         if (limit && end_pfn > limit)
 192                 end_pfn = limit;
 193
 194         eidx = end_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
 195         offset = 0;
 196         if (align &&
 197             (bdata->node_boot_start & (align - 1UL)) != 0)
 198                 offset = (align - (bdata->node_boot_start & (align - 1UL)));
 199         offset >>= PAGE_SHIFT;
 200
 201         /*
 202          * We try to allocate bootmem pages above 'goal'
 203          * first, then we try to allocate lower pages.
 204          */
 205         if (goal && (goal >= bdata->node_boot_start) &&
 206             ((goal >> PAGE_SHIFT) < end_pfn)) {
 207                 preferred = goal - bdata->node_boot_start;
 208
 209                 if (bdata->last_success >= preferred)
 210                         if (!limit || (limit && limit > bdata->last_success))
 211                                 preferred = bdata->last_success;
 212         } else
 213                 preferred = 0;
 214
 215         preferred = ALIGN(preferred, align) >> PAGE_SHIFT;
 216         preferred += offset;
 217         areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
 218         incr = align >> PAGE_SHIFT ? : 1;
 219
 220 restart_scan:
 221         for (i = preferred; i < eidx; i += incr) {
 222                 unsigned long j;
 223                 i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
 224                 i = ALIGN(i, incr);
 225                 if (i >= eidx)
 226                         break;
 227                 if (test_bit(i, bdata->node_bootmem_map))
 228                         continue;
 229                 for (j = i + 1; j < i + areasize; ++j) {
 230                         if (j >= eidx)
 231                                 goto fail_block;
 232                         if (test_bit (j, bdata->node_bootmem_map))
 233                                 goto fail_block;
 234                 }
 235                 start = i;
 236                 goto found;
 237         fail_block:
 238                 i = ALIGN(j, incr);
 239         }
 240
 241         if (preferred > offset) {
 242                 preferred = offset;
 243                 goto restart_scan;
 244         }
 245         return NULL;
 246
 247 found:
 248         bdata->last_success = start << PAGE_SHIFT;
 249         BUG_ON(start >= eidx);
 250
 251         /*
 252          * Is the next page of the previous allocation-end the start
 253          * of this allocation's buffer? If yes then we can 'merge'
 254          * the previous partial page with this allocation.
 255          */
 256         if (align < PAGE_SIZE &&
 257             bdata->last_offset && bdata->last_pos+1 == start) {
 258                 offset = ALIGN(bdata->last_offset, align);
 259                 BUG_ON(offset > PAGE_SIZE);
 260                 remaining_size = PAGE_SIZE-offset;
 261                 if (size < remaining_size) {
 262                         areasize = 0;
 263                         /* last_pos unchanged */
 264                         bdata->last_offset = offset+size;
 265                         ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
 266                                                 bdata->node_boot_start);
 267                 } else {
 268                         remaining_size = size - remaining_size;
 269                         areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;
 270                         ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +
 271                                                 bdata->node_boot_start);
 272                         bdata->last_pos = start+areasize-1;
 273                         bdata->last_offset = remaining_size;
 274                 }
 275                 bdata->last_offset &= ~PAGE_MASK;
 276         } else {
 277                 bdata->last_pos = start + areasize - 1;
 278                 bdata->last_offset = size & ~PAGE_MASK;
 279                 ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
 280         }
 281
 282         /*
 283          * Reserve the area now:
 284          */
 285         for (i = start; i < start+areasize; i++)
 286                 if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
 287                         BUG();
 288         memset(ret, 0, size);
 289         return ret;
 290 }
 291
 292 static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
 293 {
 294         struct page *page;
 295         unsigned long pfn;
 296         bootmem_data_t *bdata = pgdat->bdata;
 297         unsigned long i, count, total = 0;
 298         unsigned long idx;
 299         unsigned long *map;
 300         int gofast = 0;
 301
 302         BUG_ON(!bdata->node_bootmem_map);
 303
 304         count = 0;
 305         /* first extant page of the node */
 306         pfn = bdata->node_boot_start >> PAGE_SHIFT;
 307         idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);
 308         map = bdata->node_bootmem_map;
 309         /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
 310         if (bdata->node_boot_start == 0 ||
 311             ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
 312                 gofast = 1;
 313         for (i = 0; i < idx; ) {
 314                 unsigned long v = ~map[i / BITS_PER_LONG];
 315
 316                 if (gofast && v == ~0UL) {
 317                         int order;
 318
 319                         page = pfn_to_page(pfn);
 320                         count += BITS_PER_LONG;
 321                         order = ffs(BITS_PER_LONG) - 1;
 322                         __free_pages_bootmem(page, order);
 323                         i += BITS_PER_LONG;
 324                         page += BITS_PER_LONG;
 325                 } else if (v) {
 326                         unsigned long m;
 327
 328                         page = pfn_to_page(pfn);
 329                         for (m = 1; m && i < idx; m<<=1, page++, i++) {
 330                                 if (v & m) {
 331                                         count++;
 332                                         __free_pages_bootmem(page, 0);
 333                                 }
 334                         }
 335                 } else {
 336                         i+=BITS_PER_LONG;
 337                 }
 338                 pfn += BITS_PER_LONG;
 339         }
 340         total += count;
 341
 342         /*
 343          * Now free the allocator bitmap itself, it's not
 344          * needed anymore:
 345          */
 346         page = virt_to_page(bdata->node_bootmem_map);
 347         count = 0;
 348         for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {
 349                 count++;
 350                 __free_pages_bootmem(page, 0);
 351         }
 352         total += count;
 353         bdata->node_bootmem_map = NULL;
 354
 355         return total;
 356 }
 357
 358 unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn)
 359 {
 360         return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));
 361 }
 362
 363 void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
 364 {
 365         reserve_bootmem_core(pgdat->bdata, physaddr, size);
 366 }
 367
 368 void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size)
 369 {
 370         free_bootmem_core(pgdat->bdata, physaddr, size);
 371 }
 372
 373 unsigned long __init free_all_bootmem_node (pg_data_t *pgdat)
 374 {
 375         return(free_all_bootmem_core(pgdat));
 376 }
 377
 378 unsigned long __init init_bootmem (unsigned long start, unsigned long pages)
 379 {
 380         max_low_pfn = pages;
 381         min_low_pfn = start;
 382         return(init_bootmem_core(NODE_DATA(0), start, 0, pages));
 383 }
 384
 385 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
 386 void __init reserve_bootmem (unsigned long addr, unsigned long size)
 387 {
 388         reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);
 389 }
 390 #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
 391
 392 void __init free_bootmem (unsigned long addr, unsigned long size)
 393 {
 394         free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
 395 }
 396
 397 unsigned long __init free_all_bootmem (void)
 398 {
 399         return(free_all_bootmem_core(NODE_DATA(0)));
 400 }
 401
 402 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align, unsigned long goal)
 403 {
 404         bootmem_data_t *bdata;
 405         void *ptr;
 406
 407         list_for_each_entry(bdata, &bdata_list, list)
 408                 if ((ptr = __alloc_bootmem_core(bdata, size, align, goal, 0)))
 409                         return(ptr);
 410         return NULL;
 411 }
 412
 413 void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal)
 414 {
 415         void *mem = __alloc_bootmem_nopanic(size,align,goal);
 416         if (mem)
 417                 return mem;
 418         /*
 419          * Whoops, we cannot satisfy the allocation request.
 420          */
 421         printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
 422         panic("Out of memory");
 423         return NULL;
 424 }
 425
 426
 427 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size, unsigned long align,
 428                                    unsigned long goal)
 429 {
 430         void *ptr;
 431
 432         ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
 433         if (ptr)
 434                 return (ptr);
 435
 436         return __alloc_bootmem(size, align, goal);
 437 }
 438
 439 #define LOW32LIMIT 0xffffffff
 440
 441 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align, unsigned long goal)
 442 {
 443         bootmem_data_t *bdata;
 444         void *ptr;
 445
 446         list_for_each_entry(bdata, &bdata_list, list)
 447                 if ((ptr = __alloc_bootmem_core(bdata, size,
 448                                                  align, goal, LOW32LIMIT)))
 449                         return(ptr);
 450
 451         /*
 452          * Whoops, we cannot satisfy the allocation request.
 453          */
 454         printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);
 455         panic("Out of low memory");
 456         return NULL;
 457 }
 458
 459 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
 460                                        unsigned long align, unsigned long goal)
 461 {
 462         return __alloc_bootmem_core(pgdat->bdata, size, align, goal, LOW32LIMIT);
 463 }