diff options
Diffstat (limited to 'mm/bootmem.c')
| -rw-r--r-- | mm/bootmem.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/mm/bootmem.c b/mm/bootmem.c new file mode 100644 index 0000000..260e703 --- /dev/null +++ b/mm/bootmem.c @@ -0,0 +1,400 @@ +/* + * linux/mm/bootmem.c + * + * Copyright (C) 1999 Ingo Molnar + * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999 + * + * simple boot-time physical memory area allocator and + * free memory collector. It's used to deal with reserved + * system memory and memory holes as well. + */ + +#include <linux/mm.h> +#include <linux/kernel_stat.h> +#include <linux/swap.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/bootmem.h> +#include <linux/mmzone.h> +#include <linux/module.h> +#include <asm/dma.h> +#include <asm/io.h> +#include "internal.h" + +/* + * Access to this subsystem has to be serialized externally. (this is + * true for the boot process anyway) + */ +unsigned long max_low_pfn; +unsigned long min_low_pfn; +unsigned long max_pfn; + +EXPORT_SYMBOL(max_pfn); /* This is exported so + * dma_get_required_mask(), which uses + * it, can be an inline function */ + +/* return the number of _pages_ that will be allocated for the boot bitmap */ +unsigned long __init bootmem_bootmap_pages (unsigned long pages) +{ + unsigned long mapsize; + + mapsize = (pages+7)/8; + mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK; + mapsize >>= PAGE_SHIFT; + + return mapsize; +} + +/* + * Called once to set up the allocator itself. + */ +static unsigned long __init init_bootmem_core (pg_data_t *pgdat, + unsigned long mapstart, unsigned long start, unsigned long end) +{ + bootmem_data_t *bdata = pgdat->bdata; + unsigned long mapsize = ((end - start)+7)/8; + + pgdat->pgdat_next = pgdat_list; + pgdat_list = pgdat; + + mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL); + bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT); + bdata->node_boot_start = (start << PAGE_SHIFT); + bdata->node_low_pfn = end; + + /* + * Initially all pages are reserved - setup_arch() has to + * register free RAM areas explicitly. + */ + memset(bdata->node_bootmem_map, 0xff, mapsize); + + return mapsize; +} + +/* + * Marks a particular physical memory range as unallocatable. Usable RAM + * might be used for boot-time allocations - or it might get added + * to the free page pool later on. + */ +static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size) +{ + unsigned long i; + /* + * round up, partially reserved pages are considered + * fully reserved. + */ + unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE; + unsigned long eidx = (addr + size - bdata->node_boot_start + + PAGE_SIZE-1)/PAGE_SIZE; + unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE; + + BUG_ON(!size); + BUG_ON(sidx >= eidx); + BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn); + BUG_ON(end > bdata->node_low_pfn); + + for (i = sidx; i < eidx; i++) + if (test_and_set_bit(i, bdata->node_bootmem_map)) { +#ifdef CONFIG_DEBUG_BOOTMEM + printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE); +#endif + } +} + +static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size) +{ + unsigned long i; + unsigned long start; + /* + * round down end of usable mem, partially free pages are + * considered reserved. + */ + unsigned long sidx; + unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE; + unsigned long end = (addr + size)/PAGE_SIZE; + + BUG_ON(!size); + BUG_ON(end > bdata->node_low_pfn); + + if (addr < bdata->last_success) + bdata->last_success = addr; + + /* + * Round up the beginning of the address. + */ + start = (addr + PAGE_SIZE-1) / PAGE_SIZE; + sidx = start - (bdata->node_boot_start/PAGE_SIZE); + + for (i = sidx; i < eidx; i++) { + if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map))) + BUG(); + } +} + +/* + * We 'merge' subsequent allocations to save space. We might 'lose' + * some fraction of a page if allocations cannot be satisfied due to + * size constraints on boxes where there is physical RAM space + * fragmentation - in these cases (mostly large memory boxes) this + * is not a problem. + * + * On low memory boxes we get it right in 100% of the cases. + * + * alignment has to be a power of 2 value. + * + * NOTE: This function is _not_ reentrant. + */ +static void * __init +__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size, + unsigned long align, unsigned long goal) +{ + unsigned long offset, remaining_size, areasize, preferred; + unsigned long i, start = 0, incr, eidx; + void *ret; + + if(!size) { + printk("__alloc_bootmem_core(): zero-sized request\n"); + BUG(); + } + BUG_ON(align & (align-1)); + + eidx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT); + offset = 0; + if (align && + (bdata->node_boot_start & (align - 1UL)) != 0) + offset = (align - (bdata->node_boot_start & (align - 1UL))); + offset >>= PAGE_SHIFT; + + /* + * We try to allocate bootmem pages above 'goal' + * first, then we try to allocate lower pages. + */ + if (goal && (goal >= bdata->node_boot_start) && + ((goal >> PAGE_SHIFT) < bdata->node_low_pfn)) { + preferred = goal - bdata->node_boot_start; + + if (bdata->last_success >= preferred) + preferred = bdata->last_success; + } else + preferred = 0; + + preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT; + preferred += offset; + areasize = (size+PAGE_SIZE-1)/PAGE_SIZE; + incr = align >> PAGE_SHIFT ? : 1; + +restart_scan: + for (i = preferred; i < eidx; i += incr) { + unsigned long j; + i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i); + i = ALIGN(i, incr); + if (test_bit(i, bdata->node_bootmem_map)) + continue; + for (j = i + 1; j < i + areasize; ++j) { + if (j >= eidx) + goto fail_block; + if (test_bit (j, bdata->node_bootmem_map)) + goto fail_block; + } + start = i; + goto found; + fail_block: + i = ALIGN(j, incr); + } + + if (preferred > offset) { + preferred = offset; + goto restart_scan; + } + return NULL; + +found: + bdata->last_success = start << PAGE_SHIFT; + BUG_ON(start >= eidx); + + /* + * Is the next page of the previous allocation-end the start + * of this allocation's buffer? If yes then we can 'merge' + * the previous partial page with this allocation. + */ + if (align < PAGE_SIZE && + bdata->last_offset && bdata->last_pos+1 == start) { + offset = (bdata->last_offset+align-1) & ~(align-1); + BUG_ON(offset > PAGE_SIZE); + remaining_size = PAGE_SIZE-offset; + if (size < remaining_size) { + areasize = 0; + /* last_pos unchanged */ + bdata->last_offset = offset+size; + ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset + + bdata->node_boot_start); + } else { + remaining_size = size - remaining_size; + areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE; + ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset + + bdata->node_boot_start); + bdata->last_pos = start+areasize-1; + bdata->last_offset = remaining_size; + } + bdata->last_offset &= ~PAGE_MASK; + } else { + bdata->last_pos = start + areasize - 1; + bdata->last_offset = size & ~PAGE_MASK; + ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start); + } + + /* + * Reserve the area now: + */ + for (i = start; i < start+areasize; i++) + if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map))) + BUG(); + memset(ret, 0, size); + return ret; +} + +static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat) +{ + struct page *page; + bootmem_data_t *bdata = pgdat->bdata; + unsigned long i, count, total = 0; + unsigned long idx; + unsigned long *map; + int gofast = 0; + + BUG_ON(!bdata->node_bootmem_map); + + count = 0; + /* first extant page of the node */ + page = virt_to_page(phys_to_virt(bdata->node_boot_start)); + idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT); + map = bdata->node_bootmem_map; + /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */ + if (bdata->node_boot_start == 0 || + ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG)) + gofast = 1; + for (i = 0; i < idx; ) { + unsigned long v = ~map[i / BITS_PER_LONG]; + if (gofast && v == ~0UL) { + int j, order; + + count += BITS_PER_LONG; + __ClearPageReserved(page); + order = ffs(BITS_PER_LONG) - 1; + set_page_refs(page, order); + for (j = 1; j < BITS_PER_LONG; j++) { + if (j + 16 < BITS_PER_LONG) + prefetchw(page + j + 16); + __ClearPageReserved(page + j); + } + __free_pages(page, order); + i += BITS_PER_LONG; + page += BITS_PER_LONG; + } else if (v) { + unsigned long m; + for (m = 1; m && i < idx; m<<=1, page++, i++) { + if (v & m) { + count++; + __ClearPageReserved(page); + set_page_refs(page, 0); + __free_page(page); + } + } + } else { + i+=BITS_PER_LONG; + page += BITS_PER_LONG; + } + } + total += count; + + /* + * Now free the allocator bitmap itself, it's not + * needed anymore: + */ + page = virt_to_page(bdata->node_bootmem_map); + count = 0; + for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) { + count++; + __ClearPageReserved(page); + set_page_count(page, 1); + __free_page(page); + } + total += count; + bdata->node_bootmem_map = NULL; + + return total; +} + +unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn) +{ + return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn)); +} + +void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size) +{ + reserve_bootmem_core(pgdat->bdata, physaddr, size); +} + +void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size) +{ + free_bootmem_core(pgdat->bdata, physaddr, size); +} + +unsigned long __init free_all_bootmem_node (pg_data_t *pgdat) +{ + return(free_all_bootmem_core(pgdat)); +} + +unsigned long __init init_bootmem (unsigned long start, unsigned long pages) +{ + max_low_pfn = pages; + min_low_pfn = start; + return(init_bootmem_core(NODE_DATA(0), start, 0, pages)); +} + +#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE +void __init reserve_bootmem (unsigned long addr, unsigned long size) +{ + reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size); +} +#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */ + +void __init free_bootmem (unsigned long addr, unsigned long size) +{ + free_bootmem_core(NODE_DATA(0)->bdata, addr, size); +} + +unsigned long __init free_all_bootmem (void) +{ + return(free_all_bootmem_core(NODE_DATA(0))); +} + +void * __init __alloc_bootmem (unsigned long size, unsigned long align, unsigned long goal) +{ + pg_data_t *pgdat = pgdat_list; + void *ptr; + + for_each_pgdat(pgdat) + if ((ptr = __alloc_bootmem_core(pgdat->bdata, size, + align, goal))) + return(ptr); + + /* + * Whoops, we cannot satisfy the allocation request. + */ + printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size); + panic("Out of memory"); + return NULL; +} + +void * __init __alloc_bootmem_node (pg_data_t *pgdat, unsigned long size, unsigned long align, unsigned long goal) +{ + void *ptr; + + ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal); + if (ptr) + return (ptr); + + return __alloc_bootmem(size, align, goal); +} + |
