Subversion Repositories test_project

/*

 *  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/init.h>

#include <linux/pfn.h>

#include <linux/bootmem.h>

#include <linux/module.h>

#include <asm/bug.h>

#include <asm/io.h>

#include <asm/processor.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;

static LIST_HEAD(bdata_list);

#ifdef CONFIG_CRASH_DUMP

/*

 * If we have booted due to a crash, max_pfn will be a very low value. We need

 * to know the amount of memory that the previous kernel used.

 */

unsigned long saved_max_pfn;

#endif

/* 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;

}

/*

 * link bdata in order

 */

static void __init link_bootmem(bootmem_data_t *bdata)

{

        bootmem_data_t *ent;

        if (list_empty(&bdata_list)) {

                list_add(&bdata->list, &bdata_list);

                return;

        }

        /* insert in order */

        list_for_each_entry(ent, &bdata_list, list) {

                if (bdata->node_boot_start < ent->node_boot_start) {

                        list_add_tail(&bdata->list, &ent->list);

                        return;

                }

        }

        list_add_tail(&bdata->list, &bdata_list);

}

/*

 * Given an initialised bdata, it returns the size of the boot bitmap

 */

static unsigned long __init get_mapsize(bootmem_data_t *bdata)

{

        unsigned long mapsize;

        unsigned long start = PFN_DOWN(bdata->node_boot_start);

        unsigned long end = bdata->node_low_pfn;

        mapsize = ((end - start) + 7) / 8;

        return ALIGN(mapsize, sizeof(long));

}

/*

 * 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;

        bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));

        bdata->node_boot_start = PFN_PHYS(start);

        bdata->node_low_pfn = end;

        link_bootmem(bdata);

        /*

         * Initially all pages are reserved - setup_arch() has to

         * register free RAM areas explicitly.

         */

        mapsize = get_mapsize(bdata);

        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 sidx, eidx;

        unsigned long i;

        /*

         * round up, partially reserved pages are considered

         * fully reserved.

         */

        BUG_ON(!size);

        BUG_ON(PFN_DOWN(addr) >= bdata->node_low_pfn);

        BUG_ON(PFN_UP(addr + size) > bdata->node_low_pfn);

        sidx = PFN_DOWN(addr - bdata->node_boot_start);

        eidx = PFN_UP(addr + size - bdata->node_boot_start);

        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 sidx, eidx;

        unsigned long i;

        /*

         * round down end of usable mem, partially free pages are

         * considered reserved.

         */

        BUG_ON(!size);

        BUG_ON(PFN_DOWN(addr + size) > bdata->node_low_pfn);

        if (addr < bdata->last_success)

                bdata->last_success = addr;

        /*

         * Round up the beginning of the address.

         */

        sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);

        eidx = PFN_DOWN(addr + size - bdata->node_boot_start);

        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.

 */

void * __init

__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,

              unsigned long align, unsigned long goal, unsigned long limit)

{

        unsigned long offset, remaining_size, areasize, preferred;

        unsigned long i, start = 0, incr, eidx, end_pfn;

        void *ret;

        if (!size) {

                printk("__alloc_bootmem_core(): zero-sized request\n");

                BUG();

        }

        BUG_ON(align & (align-1));

        if (limit && bdata->node_boot_start >= limit)

                return NULL;

        /* on nodes without memory - bootmem_map is NULL */

        if (!bdata->node_bootmem_map)

                return NULL;

        end_pfn = bdata->node_low_pfn;

        limit = PFN_DOWN(limit);

        if (limit && end_pfn > limit)

                end_pfn = limit;

        eidx = end_pfn - PFN_DOWN(bdata->node_boot_start);

        offset = 0;

        if (align && (bdata->node_boot_start & (align - 1UL)) != 0)

                offset = align - (bdata->node_boot_start & (align - 1UL));

        offset = PFN_DOWN(offset);

        /*

         * We try to allocate bootmem pages above 'goal'

         * first, then we try to allocate lower pages.

         */

        if (goal && goal >= bdata->node_boot_start && PFN_DOWN(goal) < end_pfn) {

                preferred = goal - bdata->node_boot_start;

                if (bdata->last_success >= preferred)

                        if (!limit || (limit && limit > bdata->last_success))

                                preferred = bdata->last_success;

        } else

                preferred = 0;

        preferred = PFN_DOWN(ALIGN(preferred, align)) + 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 (i >= eidx)

                        break;

                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 = PFN_PHYS(start);

        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 = ALIGN(bdata->last_offset, align);

                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;

        unsigned long pfn;

        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 */

        pfn = PFN_DOWN(bdata->node_boot_start);

        idx = bdata->node_low_pfn - pfn;

        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 order;

                        page = pfn_to_page(pfn);

                        count += BITS_PER_LONG;

                        order = ffs(BITS_PER_LONG) - 1;

                        __free_pages_bootmem(page, order);

                        i += BITS_PER_LONG;

                        page += BITS_PER_LONG;

                } else if (v) {

                        unsigned long m;

                        page = pfn_to_page(pfn);

                        for (m = 1; m && i < idx; m<<=1, page++, i++) {

                                if (v & m) {

                                        count++;

                                        __free_pages_bootmem(page, 0);

                                }

                        }

                } else {

                        i += BITS_PER_LONG;

                }

                pfn += 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;

        idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;

        for (i = 0; i < idx; i++, page++) {

                __free_pages_bootmem(page, 0);

                count++;

        }

        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_nopanic(unsigned long size, unsigned long align,

                                      unsigned long goal)

{

        bootmem_data_t *bdata;

        void *ptr;

        list_for_each_entry(bdata, &bdata_list, list) {

                ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);

                if (ptr)

                        return ptr;

        }

        return NULL;

}

void * __init __alloc_bootmem(unsigned long size, unsigned long align,

                              unsigned long goal)

{

        void *mem = __alloc_bootmem_nopanic(size,align,goal);

        if (mem)

                return mem;

        /*

         * 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, 0);

        if (ptr)

                return ptr;

        return __alloc_bootmem(size, align, goal);

}

#ifndef ARCH_LOW_ADDRESS_LIMIT

#define ARCH_LOW_ADDRESS_LIMIT  0xffffffffUL

#endif

void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,

                                  unsigned long goal)

{

        bootmem_data_t *bdata;

        void *ptr;

        list_for_each_entry(bdata, &bdata_list, list) {

                ptr = __alloc_bootmem_core(bdata, size, align, goal,

                                                ARCH_LOW_ADDRESS_LIMIT);

                if (ptr)

                        return ptr;

        }

        /*

         * Whoops, we cannot satisfy the allocation request.

         */

        printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);

        panic("Out of low memory");

        return NULL;

}

void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,

                                       unsigned long align, unsigned long goal)

{

        return __alloc_bootmem_core(pgdat->bdata, size, align, goal,

                                    ARCH_LOW_ADDRESS_LIMIT);

}