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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 | /* * linux/mm/page_alloc.c * * Manages the free list, the system allocates free pages here. * Note that kmalloc() lives in slab.c * * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * Swap reorganised 29.12.95, Stephen Tweedie * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999 * Zone balancing, Kanoj Sarcar, SGI, Jan 2000 */ #include <linux/config.h> #include <linux/mm.h> #include <linux/swap.h> #include <linux/swapctl.h> #include <linux/interrupt.h> #include <linux/pagemap.h> #include <linux/bootmem.h> #include <linux/slab.h> #include <linux/compiler.h> #include <linux/module.h> int nr_swap_pages; int nr_active_pages; int nr_inactive_pages; struct list_head inactive_list; struct list_head active_list; pg_data_t *pgdat_list; /* Used to look up the address of the struct zone encoded in page->zone */ zone_t *zone_table[MAX_NR_ZONES*MAX_NR_NODES]; EXPORT_SYMBOL(zone_table); static char *zone_names[MAX_NR_ZONES] = { "DMA", "Normal", "HighMem" }; static int zone_balance_ratio[MAX_NR_ZONES] __initdata = { 128, 128, 128, }; static int zone_balance_min[MAX_NR_ZONES] __initdata = { 20 , 20, 20, }; static int zone_balance_max[MAX_NR_ZONES] __initdata = { 255 , 255, 255, }; /* * Free_page() adds the page to the free lists. This is optimized for * fast normal cases (no error jumps taken normally). * * The way to optimize jumps for gcc-2.2.2 is to: * - select the "normal" case and put it inside the if () { XXX } * - no else-statements if you can avoid them * * With the above two rules, you get a straight-line execution path * for the normal case, giving better asm-code. */ #define memlist_init(x) INIT_LIST_HEAD(x) #define memlist_add_head list_add #define memlist_add_tail list_add_tail #define memlist_del list_del #define memlist_entry list_entry #define memlist_next(x) ((x)->next) #define memlist_prev(x) ((x)->prev) /* * Temporary debugging check. */ #define BAD_RANGE(zone, page) \ ( \ (((page) - mem_map) >= ((zone)->zone_start_mapnr+(zone)->size)) \ || (((page) - mem_map) < (zone)->zone_start_mapnr) \ || ((zone) != page_zone(page)) \ ) /* * Freeing function for a buddy system allocator. * * The concept of a buddy system is to maintain direct-mapped table * (containing bit values) for memory blocks of various "orders". * The bottom level table contains the map for the smallest allocatable * units of memory (here, pages), and each level above it describes * pairs of units from the levels below, hence, "buddies". * At a high level, all that happens here is marking the table entry * at the bottom level available, and propagating the changes upward * as necessary, plus some accounting needed to play nicely with other * parts of the VM system. * * TODO: give references to descriptions of buddy system allocators, * describe precisely the silly trick buddy allocators use to avoid * storing an extra bit, utilizing entry point information. * * -- wli */ static void FASTCALL(__free_pages_ok (struct page *page, unsigned int order)); static void __free_pages_ok (struct page *page, unsigned int order) { unsigned long index, page_idx, mask, flags; free_area_t *area; struct page *base; zone_t *zone; if (page->buffers) BUG(); if (page->mapping) BUG(); if (!VALID_PAGE(page)) BUG(); if (PageSwapCache(page)) BUG(); if (PageLocked(page)) BUG(); if (PageLRU(page)) BUG(); if (PageActive(page)) BUG(); page->flags &= ~((1<<PG_referenced) | (1<<PG_dirty)); if (current->flags & PF_FREE_PAGES) goto local_freelist; back_local_freelist: zone = page_zone(page); mask = (~0UL) << order; base = zone->zone_mem_map; page_idx = page - base; if (page_idx & ~mask) BUG(); index = page_idx >> (1 + order); area = zone->free_area + order; spin_lock_irqsave(&zone->lock, flags); zone->free_pages -= mask; while (mask + (1 << (MAX_ORDER-1))) { struct page *buddy1, *buddy2; if (area >= zone->free_area + MAX_ORDER) BUG(); if (!__test_and_change_bit(index, area->map)) /* * the buddy page is still allocated. */ break; /* * Move the buddy up one level. * This code is taking advantage of the identity: * -mask = 1+~mask */ buddy1 = base + (page_idx ^ -mask); buddy2 = base + page_idx; if (BAD_RANGE(zone,buddy1)) BUG(); if (BAD_RANGE(zone,buddy2)) BUG(); memlist_del(&buddy1->list); mask <<= 1; area++; index >>= 1; page_idx &= mask; } memlist_add_head(&(base + page_idx)->list, &area->free_list); spin_unlock_irqrestore(&zone->lock, flags); return; local_freelist: if (current->nr_local_pages) goto back_local_freelist; if (in_interrupt()) goto back_local_freelist; list_add(&page->list, ¤t->local_pages); page->index = order; current->nr_local_pages++; } #define MARK_USED(index, order, area) \ __change_bit((index) >> (1+(order)), (area)->map) static inline struct page * expand (zone_t *zone, struct page *page, unsigned long index, int low, int high, free_area_t * area) { unsigned long size = 1 << high; while (high > low) { if (BAD_RANGE(zone,page)) BUG(); area--; high--; size >>= 1; memlist_add_head(&(page)->list, &(area)->free_list); MARK_USED(index, high, area); index += size; page += size; } if (BAD_RANGE(zone,page)) BUG(); return page; } static FASTCALL(struct page * rmqueue(zone_t *zone, unsigned int order)); static struct page * rmqueue(zone_t *zone, unsigned int order) { free_area_t * area = zone->free_area + order; unsigned int curr_order = order; struct list_head *head, *curr; unsigned long flags; struct page *page; spin_lock_irqsave(&zone->lock, flags); do { head = &area->free_list; curr = memlist_next(head); if (curr != head) { unsigned int index; page = memlist_entry(curr, struct page, list); if (BAD_RANGE(zone,page)) BUG(); memlist_del(curr); index = page - zone->zone_mem_map; if (curr_order != MAX_ORDER-1) MARK_USED(index, curr_order, area); zone->free_pages -= 1UL << order; page = expand(zone, page, index, order, curr_order, area); spin_unlock_irqrestore(&zone->lock, flags); set_page_count(page, 1); if (BAD_RANGE(zone,page)) BUG(); if (PageLRU(page)) BUG(); if (PageActive(page)) BUG(); return page; } curr_order++; area++; } while (curr_order < MAX_ORDER); spin_unlock_irqrestore(&zone->lock, flags); return NULL; } #ifndef CONFIG_DISCONTIGMEM struct page *_alloc_pages(unsigned int gfp_mask, unsigned int order) { return __alloc_pages(gfp_mask, order, contig_page_data.node_zonelists+(gfp_mask & GFP_ZONEMASK)); } #endif static struct page * FASTCALL(balance_classzone(zone_t *, unsigned int, unsigned int, int *)); static struct page * balance_classzone(zone_t * classzone, unsigned int gfp_mask, unsigned int order, int * freed) { struct page * page = NULL; int __freed = 0; if (!(gfp_mask & __GFP_WAIT)) goto out; if (in_interrupt()) BUG(); current->allocation_order = order; current->flags |= PF_MEMALLOC | PF_FREE_PAGES; __freed = try_to_free_pages(classzone, gfp_mask, order); current->flags &= ~(PF_MEMALLOC | PF_FREE_PAGES); if (current->nr_local_pages) { struct list_head * entry, * local_pages; struct page * tmp; int nr_pages; local_pages = ¤t->local_pages; if (likely(__freed)) { /* pick from the last inserted so we're lifo */ entry = local_pages->next; do { tmp = list_entry(entry, struct page, list); if (tmp->index == order && memclass(page_zone(tmp), classzone)) { list_del(entry); current->nr_local_pages--; set_page_count(tmp, 1); page = tmp; if (page->buffers) BUG(); if (page->mapping) BUG(); if (!VALID_PAGE(page)) BUG(); if (PageSwapCache(page)) BUG(); if (PageLocked(page)) BUG(); if (PageLRU(page)) BUG(); if (PageActive(page)) BUG(); if (PageDirty(page)) BUG(); break; } } while ((entry = entry->next) != local_pages); } nr_pages = current->nr_local_pages; /* free in reverse order so that the global order will be lifo */ while ((entry = local_pages->prev) != local_pages) { list_del(entry); tmp = list_entry(entry, struct page, list); __free_pages_ok(tmp, tmp->index); if (!nr_pages--) BUG(); } current->nr_local_pages = 0; } out: *freed = __freed; return page; } /* * This is the 'heart' of the zoned buddy allocator: */ struct page * __alloc_pages(unsigned int gfp_mask, unsigned int order, zonelist_t *zonelist) { unsigned long min; zone_t **zone, * classzone; struct page * page; int freed; zone = zonelist->zones; classzone = *zone; min = 1UL << order; for (;;) { zone_t *z = *(zone++); if (!z) break; min += z->pages_low; if (z->free_pages > min) { page = rmqueue(z, order); if (page) return page; } } classzone->need_balance = 1; mb(); if (waitqueue_active(&kswapd_wait)) wake_up_interruptible(&kswapd_wait); zone = zonelist->zones; min = 1UL << order; for (;;) { unsigned long local_min; zone_t *z = *(zone++); if (!z) break; local_min = z->pages_min; if (!(gfp_mask & __GFP_WAIT)) local_min >>= 2; min += local_min; if (z->free_pages > min) { page = rmqueue(z, order); if (page) return page; } } /* here we're in the low on memory slow path */ rebalance: if (current->flags & (PF_MEMALLOC | PF_MEMDIE)) { zone = zonelist->zones; for (;;) { zone_t *z = *(zone++); if (!z) break; page = rmqueue(z, order); if (page) return page; } return NULL; } /* Atomic allocations - we can't balance anything */ if (!(gfp_mask & __GFP_WAIT)) return NULL; page = balance_classzone(classzone, gfp_mask, order, &freed); if (page) return page; zone = zonelist->zones; min = 1UL << order; for (;;) { zone_t *z = *(zone++); if (!z) break; min += z->pages_min; if (z->free_pages > min) { page = rmqueue(z, order); if (page) return page; } } /* Don't let big-order allocations loop */ if (order > 3) return NULL; /* Yield for kswapd, and try again */ __set_current_state(TASK_RUNNING); yield(); goto rebalance; } /* * Common helper functions. */ unsigned long __get_free_pages(unsigned int gfp_mask, unsigned int order) { struct page * page; page = alloc_pages(gfp_mask, order); if (!page) return 0; return (unsigned long) page_address(page); } unsigned long get_zeroed_page(unsigned int gfp_mask) { struct page * page; page = alloc_pages(gfp_mask, 0); if (page) { void *address = page_address(page); clear_page(address); return (unsigned long) address; } return 0; } void page_cache_release(struct page *page) { if (!PageReserved(page) && put_page_testzero(page)) { if (PageLRU(page)) lru_cache_del(page); __free_pages_ok(page, 0); } } void __free_pages(struct page *page, unsigned int order) { if (!PageReserved(page) && put_page_testzero(page)) __free_pages_ok(page, order); } void free_pages(unsigned long addr, unsigned int order) { if (addr != 0) __free_pages(virt_to_page(addr), order); } /* * Total amount of free (allocatable) RAM: */ unsigned int nr_free_pages (void) { unsigned int sum; zone_t *zone; pg_data_t *pgdat = pgdat_list; sum = 0; while (pgdat) { for (zone = pgdat->node_zones; zone < pgdat->node_zones + MAX_NR_ZONES; zone++) sum += zone->free_pages; pgdat = pgdat->node_next; } return sum; } /* * Amount of free RAM allocatable as buffer memory: */ unsigned int nr_free_buffer_pages (void) { pg_data_t *pgdat = pgdat_list; unsigned int sum = 0; do { zonelist_t *zonelist = pgdat->node_zonelists + (GFP_USER & GFP_ZONEMASK); zone_t **zonep = zonelist->zones; zone_t *zone; for (zone = *zonep++; zone; zone = *zonep++) { unsigned long size = zone->size; unsigned long high = zone->pages_high; if (size > high) sum += size - high; } pgdat = pgdat->node_next; } while (pgdat); return sum; } #if CONFIG_HIGHMEM unsigned int nr_free_highpages (void) { pg_data_t *pgdat = pgdat_list; unsigned int pages = 0; while (pgdat) { pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages; pgdat = pgdat->node_next; } return pages; } #endif #define K(x) ((x) << (PAGE_SHIFT-10)) /* * Show free area list (used inside shift_scroll-lock stuff) * We also calculate the percentage fragmentation. We do this by counting the * memory on each free list with the exception of the first item on the list. */ void show_free_areas_core(pg_data_t *pgdat) { unsigned int order; unsigned type; pg_data_t *tmpdat = pgdat; printk("Free pages: %6dkB (%6dkB HighMem)\n", K(nr_free_pages()), K(nr_free_highpages())); while (tmpdat) { zone_t *zone; for (zone = tmpdat->node_zones; zone < tmpdat->node_zones + MAX_NR_ZONES; zone++) printk("Zone:%s freepages:%6lukB min:%6lukB low:%6lukB " "high:%6lukB\n", zone->name, K(zone->free_pages), K(zone->pages_min), K(zone->pages_low), K(zone->pages_high)); tmpdat = tmpdat->node_next; } printk("( Active: %d, inactive: %d, free: %d )\n", nr_active_pages, nr_inactive_pages, nr_free_pages()); for (type = 0; type < MAX_NR_ZONES; type++) { struct list_head *head, *curr; zone_t *zone = pgdat->node_zones + type; unsigned long nr, total, flags; total = 0; if (zone->size) { spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { head = &(zone->free_area + order)->free_list; curr = head; nr = 0; for (;;) { curr = memlist_next(curr); if (curr == head) break; nr++; } total += nr * (1 << order); printk("%lu*%lukB ", nr, K(1UL) << order); } spin_unlock_irqrestore(&zone->lock, flags); } printk("= %lukB)\n", K(total)); } #ifdef SWAP_CACHE_INFO show_swap_cache_info(); #endif } void show_free_areas(void) { show_free_areas_core(pgdat_list); } /* * Builds allocation fallback zone lists. */ static inline void build_zonelists(pg_data_t *pgdat) { int i, j, k; for (i = 0; i <= GFP_ZONEMASK; i++) { zonelist_t *zonelist; zone_t *zone; zonelist = pgdat->node_zonelists + i; memset(zonelist, 0, sizeof(*zonelist)); j = 0; k = ZONE_NORMAL; if (i & __GFP_HIGHMEM) k = ZONE_HIGHMEM; if (i & __GFP_DMA) k = ZONE_DMA; switch (k) { default: BUG(); /* * fallthrough: */ case ZONE_HIGHMEM: zone = pgdat->node_zones + ZONE_HIGHMEM; if (zone->size) { #ifndef CONFIG_HIGHMEM BUG(); #endif zonelist->zones[j++] = zone; } case ZONE_NORMAL: zone = pgdat->node_zones + ZONE_NORMAL; if (zone->size) zonelist->zones[j++] = zone; case ZONE_DMA: zone = pgdat->node_zones + ZONE_DMA; if (zone->size) zonelist->zones[j++] = zone; } zonelist->zones[j++] = NULL; } } /* * Helper functions to size the waitqueue hash table. * Essentially these want to choose hash table sizes sufficiently * large so that collisions trying to wait on pages are rare. * But in fact, the number of active page waitqueues on typical * systems is ridiculously low, less than 200. So this is even * conservative, even though it seems large. * * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to * waitqueues, i.e. the size of the waitq table given the number of pages. */ #define PAGES_PER_WAITQUEUE 256 static inline unsigned long wait_table_size(unsigned long pages) { unsigned long size = 1; pages /= PAGES_PER_WAITQUEUE; while (size < pages) size <<= 1; /* * Once we have dozens or even hundreds of threads sleeping * on IO we've got bigger problems than wait queue collision. * Limit the size of the wait table to a reasonable size. */ size = min(size, 4096UL); return size; } /* * This is an integer logarithm so that shifts can be used later * to extract the more random high bits from the multiplicative * hash function before the remainder is taken. */ static inline unsigned long wait_table_bits(unsigned long size) { return ffz(~size); } #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1)) /* * Set up the zone data structures: * - mark all pages reserved * - mark all memory queues empty * - clear the memory bitmaps */ void __init free_area_init_core(int nid, pg_data_t *pgdat, struct page **gmap, unsigned long *zones_size, unsigned long zone_start_paddr, unsigned long *zholes_size, struct page *lmem_map) { unsigned long i, j; unsigned long map_size; unsigned long totalpages, offset, realtotalpages; const unsigned long zone_required_alignment = 1UL << (MAX_ORDER-1); if (zone_start_paddr & ~PAGE_MASK) BUG(); totalpages = 0; for (i = 0; i < MAX_NR_ZONES; i++) { unsigned long size = zones_size[i]; totalpages += size; } realtotalpages = totalpages; if (zholes_size) for (i = 0; i < MAX_NR_ZONES; i++) realtotalpages -= zholes_size[i]; printk("On node %d totalpages: %lu\n", nid, realtotalpages); INIT_LIST_HEAD(&active_list); INIT_LIST_HEAD(&inactive_list); /* * Some architectures (with lots of mem and discontinous memory * maps) have to search for a good mem_map area: * For discontigmem, the conceptual mem map array starts from * PAGE_OFFSET, we need to align the actual array onto a mem map * boundary, so that MAP_NR works. */ map_size = (totalpages + 1)*sizeof(struct page); if (lmem_map == (struct page *)0) { lmem_map = (struct page *) alloc_bootmem_node(pgdat, map_size); lmem_map = (struct page *)(PAGE_OFFSET + MAP_ALIGN((unsigned long)lmem_map - PAGE_OFFSET)); } *gmap = pgdat->node_mem_map = lmem_map; pgdat->node_size = totalpages; pgdat->node_start_paddr = zone_start_paddr; pgdat->node_start_mapnr = (lmem_map - mem_map); pgdat->nr_zones = 0; offset = lmem_map - mem_map; for (j = 0; j < MAX_NR_ZONES; j++) { zone_t *zone = pgdat->node_zones + j; unsigned long mask; unsigned long size, realsize; zone_table[nid * MAX_NR_ZONES + j] = zone; realsize = size = zones_size[j]; if (zholes_size) realsize -= zholes_size[j]; printk("zone(%lu): %lu pages.\n", j, size); zone->size = size; zone->name = zone_names[j]; zone->lock = SPIN_LOCK_UNLOCKED; zone->zone_pgdat = pgdat; zone->free_pages = 0; zone->need_balance = 0; if (!size) continue; /* * The per-page waitqueue mechanism uses hashed waitqueues * per zone. */ zone->wait_table_size = wait_table_size(size); zone->wait_table_bits = wait_table_bits(zone->wait_table_size); zone->wait_table = (wait_queue_head_t *) alloc_bootmem_node(pgdat, zone->wait_table_size * sizeof(wait_queue_head_t)); for(i = 0; i < zone->wait_table_size; ++i) init_waitqueue_head(zone->wait_table + i); pgdat->nr_zones = j+1; mask = (realsize / zone_balance_ratio[j]); if (mask < zone_balance_min[j]) mask = zone_balance_min[j]; else if (mask > zone_balance_max[j]) mask = zone_balance_max[j]; zone->pages_min = mask; zone->pages_low = mask*2; zone->pages_high = mask*3; zone->zone_mem_map = mem_map + offset; zone->zone_start_mapnr = offset; zone->zone_start_paddr = zone_start_paddr; if ((zone_start_paddr >> PAGE_SHIFT) & (zone_required_alignment-1)) printk("BUG: wrong zone alignment, it will crash\n"); /* * Initially all pages are reserved - free ones are freed * up by free_all_bootmem() once the early boot process is * done. Non-atomic initialization, single-pass. */ for (i = 0; i < size; i++) { struct page *page = mem_map + offset + i; set_page_zone(page, nid * MAX_NR_ZONES + j); set_page_count(page, 0); __SetPageReserved(page); memlist_init(&page->list); if (j != ZONE_HIGHMEM) set_page_address(page, __va(zone_start_paddr)); zone_start_paddr += PAGE_SIZE; } offset += size; for (i = 0; ; i++) { unsigned long bitmap_size; memlist_init(&zone->free_area[i].free_list); if (i == MAX_ORDER-1) { zone->free_area[i].map = NULL; break; } /* * Page buddy system uses "index >> (i+1)", * where "index" is at most "size-1". * * The extra "+3" is to round down to byte * size (8 bits per byte assumption). Thus * we get "(size-1) >> (i+4)" as the last byte * we can access. * * The "+1" is because we want to round the * byte allocation up rather than down. So * we should have had a "+7" before we shifted * down by three. Also, we have to add one as * we actually _use_ the last bit (it's [0,n] * inclusive, not [0,n[). * * So we actually had +7+1 before we shift * down by 3. But (n+8) >> 3 == (n >> 3) + 1 * (modulo overflows, which we do not have). * * Finally, we LONG_ALIGN because all bitmap * operations are on longs. */ bitmap_size = (size-1) >> (i+4); bitmap_size = LONG_ALIGN(bitmap_size+1); zone->free_area[i].map = (unsigned long *) alloc_bootmem_node(pgdat, bitmap_size); } } build_zonelists(pgdat); } void __init free_area_init(unsigned long *zones_size) { free_area_init_core(0, &contig_page_data, &mem_map, zones_size, 0, 0, 0); } static int __init setup_mem_frac(char *str) { int j = 0; while (get_option(&str, &zone_balance_ratio[j++]) == 2); printk("setup_mem_frac: "); for (j = 0; j < MAX_NR_ZONES; j++) printk("%d ", zone_balance_ratio[j]); printk("\n"); return 1; } __setup("memfrac=", setup_mem_frac); |