memblock: Add arch function to control coalescing of memblock memory regions

[linux-2.6.git] / mm / memblock.c

/*
 * Procedures for maintaining information about logical memory blocks.
 *
 * Peter Bergner, IBM Corp.     June 2001.
 * Copyright (C) 2001 Peter Bergner.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/poison.h>
#include <linux/memblock.h>

struct memblock memblock;

static int memblock_debug, memblock_can_resize;
static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS + 1];
static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS + 1];

#define MEMBLOCK_ERROR  (~(phys_addr_t)0)

/* inline so we don't get a warning when pr_debug is compiled out */
static inline const char *memblock_type_name(struct memblock_type *type)
{
        if (type == &memblock.memory)
                return "memory";
        else if (type == &memblock.reserved)
                return "reserved";
        else
                return "unknown";
}

/*
 * Address comparison utilities
 */

static phys_addr_t memblock_align_down(phys_addr_t addr, phys_addr_t size)
{
        return addr & ~(size - 1);
}

static phys_addr_t memblock_align_up(phys_addr_t addr, phys_addr_t size)
{
        return (addr + (size - 1)) & ~(size - 1);
}

static unsigned long memblock_addrs_overlap(phys_addr_t base1, phys_addr_t size1,
                                       phys_addr_t base2, phys_addr_t size2)
{
        return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
}

static long memblock_addrs_adjacent(phys_addr_t base1, phys_addr_t size1,
                               phys_addr_t base2, phys_addr_t size2)
{
        if (base2 == base1 + size1)
                return 1;
        else if (base1 == base2 + size2)
                return -1;

        return 0;
}

static long memblock_regions_adjacent(struct memblock_type *type,
                                 unsigned long r1, unsigned long r2)
{
        phys_addr_t base1 = type->regions[r1].base;
        phys_addr_t size1 = type->regions[r1].size;
        phys_addr_t base2 = type->regions[r2].base;
        phys_addr_t size2 = type->regions[r2].size;

        return memblock_addrs_adjacent(base1, size1, base2, size2);
}

long memblock_overlaps_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
{
        unsigned long i;

        for (i = 0; i < type->cnt; i++) {
                phys_addr_t rgnbase = type->regions[i].base;
                phys_addr_t rgnsize = type->regions[i].size;
                if (memblock_addrs_overlap(base, size, rgnbase, rgnsize))
                        break;
        }

        return (i < type->cnt) ? i : -1;
}

/*
 * Find, allocate, deallocate or reserve unreserved regions. All allocations
 * are top-down.
 */

static phys_addr_t __init memblock_find_region(phys_addr_t start, phys_addr_t end,
                                          phys_addr_t size, phys_addr_t align)
{
        phys_addr_t base, res_base;
        long j;

        base = memblock_align_down((end - size), align);
        while (start <= base) {
                j = memblock_overlaps_region(&memblock.reserved, base, size);
                if (j < 0)
                        return base;
                res_base = memblock.reserved.regions[j].base;
                if (res_base < size)
                        break;
                base = memblock_align_down(res_base - size, align);
        }

        return MEMBLOCK_ERROR;
}

static phys_addr_t __init memblock_find_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
{
        long i;
        phys_addr_t base = 0;
        phys_addr_t res_base;

        BUG_ON(0 == size);

        size = memblock_align_up(size, align);

        /* Pump up max_addr */
        if (max_addr == MEMBLOCK_ALLOC_ACCESSIBLE)
                max_addr = memblock.current_limit;

        /* We do a top-down search, this tends to limit memory
         * fragmentation by keeping early boot allocs near the
         * top of memory
         */
        for (i = memblock.memory.cnt - 1; i >= 0; i--) {
                phys_addr_t memblockbase = memblock.memory.regions[i].base;
                phys_addr_t memblocksize = memblock.memory.regions[i].size;

                if (memblocksize < size)
                        continue;
                base = min(memblockbase + memblocksize, max_addr);
                res_base = memblock_find_region(memblockbase, base, size, align);
                if (res_base != MEMBLOCK_ERROR)
                        return res_base;
        }
        return MEMBLOCK_ERROR;
}

static void memblock_remove_region(struct memblock_type *type, unsigned long r)
{
        unsigned long i;

        for (i = r; i < type->cnt - 1; i++) {
                type->regions[i].base = type->regions[i + 1].base;
                type->regions[i].size = type->regions[i + 1].size;
        }
        type->cnt--;
}

/* Assumption: base addr of region 1 < base addr of region 2 */
static void memblock_coalesce_regions(struct memblock_type *type,
                unsigned long r1, unsigned long r2)
{
        type->regions[r1].size += type->regions[r2].size;
        memblock_remove_region(type, r2);
}

/* Defined below but needed now */
static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size);

static int memblock_double_array(struct memblock_type *type)
{
        struct memblock_region *new_array, *old_array;
        phys_addr_t old_size, new_size, addr;
        int use_slab = slab_is_available();

        /* We don't allow resizing until we know about the reserved regions
         * of memory that aren't suitable for allocation
         */
        if (!memblock_can_resize)
                return -1;

        pr_debug("memblock: %s array full, doubling...", memblock_type_name(type));

        /* Calculate new doubled size */
        old_size = type->max * sizeof(struct memblock_region);
        new_size = old_size << 1;

        /* Try to find some space for it.
         *
         * WARNING: We assume that either slab_is_available() and we use it or
         * we use MEMBLOCK for allocations. That means that this is unsafe to use
         * when bootmem is currently active (unless bootmem itself is implemented
         * on top of MEMBLOCK which isn't the case yet)
         *
         * This should however not be an issue for now, as we currently only
         * call into MEMBLOCK while it's still active, or much later when slab is
         * active for memory hotplug operations
         */
        if (use_slab) {
                new_array = kmalloc(new_size, GFP_KERNEL);
                addr = new_array == NULL ? MEMBLOCK_ERROR : __pa(new_array);
        } else
                addr = memblock_find_base(new_size, sizeof(phys_addr_t), MEMBLOCK_ALLOC_ACCESSIBLE);
        if (addr == MEMBLOCK_ERROR) {
                pr_err("memblock: Failed to double %s array from %ld to %ld entries !\n",
                       memblock_type_name(type), type->max, type->max * 2);
                return -1;
        }
        new_array = __va(addr);

        /* Found space, we now need to move the array over before
         * we add the reserved region since it may be our reserved
         * array itself that is full.
         */
        memcpy(new_array, type->regions, old_size);
        memset(new_array + type->max, 0, old_size);
        old_array = type->regions;
        type->regions = new_array;
        type->max <<= 1;

        /* If we use SLAB that's it, we are done */
        if (use_slab)
                return 0;

        /* Add the new reserved region now. Should not fail ! */
        BUG_ON(memblock_add_region(&memblock.reserved, addr, new_size) < 0);

        /* If the array wasn't our static init one, then free it. We only do
         * that before SLAB is available as later on, we don't know whether
         * to use kfree or free_bootmem_pages(). Shouldn't be a big deal
         * anyways
         */
        if (old_array != memblock_memory_init_regions &&
            old_array != memblock_reserved_init_regions)
                memblock_free(__pa(old_array), old_size);

        return 0;
}

extern int __weak memblock_memory_can_coalesce(phys_addr_t addr1, phys_addr_t size1,
                                          phys_addr_t addr2, phys_addr_t size2)
{
        return 1;
}

static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
{
        unsigned long coalesced = 0;
        long adjacent, i;

        if ((type->cnt == 1) && (type->regions[0].size == 0)) {
                type->regions[0].base = base;
                type->regions[0].size = size;
                return 0;
        }

        /* First try and coalesce this MEMBLOCK with another. */
        for (i = 0; i < type->cnt; i++) {
                phys_addr_t rgnbase = type->regions[i].base;
                phys_addr_t rgnsize = type->regions[i].size;

                if ((rgnbase == base) && (rgnsize == size))
                        /* Already have this region, so we're done */
                        return 0;

                adjacent = memblock_addrs_adjacent(base, size, rgnbase, rgnsize);
                /* Check if arch allows coalescing */
                if (adjacent != 0 && type == &memblock.memory &&
                    !memblock_memory_can_coalesce(base, size, rgnbase, rgnsize))
                        break;
                if (adjacent > 0) {
                        type->regions[i].base -= size;
                        type->regions[i].size += size;
                        coalesced++;
                        break;
                } else if (adjacent < 0) {
                        type->regions[i].size += size;
                        coalesced++;
                        break;
                }
        }

        /* If we plugged a hole, we may want to also coalesce with the
         * next region
         */
        if ((i < type->cnt - 1) && memblock_regions_adjacent(type, i, i+1) &&
            ((type != &memblock.memory || memblock_memory_can_coalesce(type->regions[i].base,
                                                             type->regions[i].size,
                                                             type->regions[i+1].base,
                                                             type->regions[i+1].size)))) {
                memblock_coalesce_regions(type, i, i+1);
                coalesced++;
        }

        if (coalesced)
                return coalesced;

        /* If we are out of space, we fail. It's too late to resize the array
         * but then this shouldn't have happened in the first place.
         */
        if (WARN_ON(type->cnt >= type->max))
                return -1;

        /* Couldn't coalesce the MEMBLOCK, so add it to the sorted table. */
        for (i = type->cnt - 1; i >= 0; i--) {
                if (base < type->regions[i].base) {
                        type->regions[i+1].base = type->regions[i].base;
                        type->regions[i+1].size = type->regions[i].size;
                } else {
                        type->regions[i+1].base = base;
                        type->regions[i+1].size = size;
                        break;
                }
        }

        if (base < type->regions[0].base) {
                type->regions[0].base = base;
                type->regions[0].size = size;
        }
        type->cnt++;

        /* The array is full ? Try to resize it. If that fails, we undo
         * our allocation and return an error
         */
        if (type->cnt == type->max && memblock_double_array(type)) {
                type->cnt--;
                return -1;
        }

        return 0;
}

long memblock_add(phys_addr_t base, phys_addr_t size)
{
        return memblock_add_region(&memblock.memory, base, size);

}

static long __memblock_remove(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
{
        phys_addr_t rgnbegin, rgnend;
        phys_addr_t end = base + size;
        int i;

        rgnbegin = rgnend = 0; /* supress gcc warnings */

        /* Find the region where (base, size) belongs to */
        for (i=0; i < type->cnt; i++) {
                rgnbegin = type->regions[i].base;
                rgnend = rgnbegin + type->regions[i].size;

                if ((rgnbegin <= base) && (end <= rgnend))
                        break;
        }

        /* Didn't find the region */
        if (i == type->cnt)
                return -1;

        /* Check to see if we are removing entire region */
        if ((rgnbegin == base) && (rgnend == end)) {
                memblock_remove_region(type, i);
                return 0;
        }

        /* Check to see if region is matching at the front */
        if (rgnbegin == base) {
                type->regions[i].base = end;
                type->regions[i].size -= size;
                return 0;
        }

        /* Check to see if the region is matching at the end */
        if (rgnend == end) {
                type->regions[i].size -= size;
                return 0;
        }

        /*
         * We need to split the entry -  adjust the current one to the
         * beginging of the hole and add the region after hole.
         */
        type->regions[i].size = base - type->regions[i].base;
        return memblock_add_region(type, end, rgnend - end);
}

long memblock_remove(phys_addr_t base, phys_addr_t size)
{
        return __memblock_remove(&memblock.memory, base, size);
}

long __init memblock_free(phys_addr_t base, phys_addr_t size)
{
        return __memblock_remove(&memblock.reserved, base, size);
}

long __init memblock_reserve(phys_addr_t base, phys_addr_t size)
{
        struct memblock_type *_rgn = &memblock.reserved;

        BUG_ON(0 == size);

        return memblock_add_region(_rgn, base, size);
}

phys_addr_t __init __memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
{
        phys_addr_t found;

        /* We align the size to limit fragmentation. Without this, a lot of
         * small allocs quickly eat up the whole reserve array on sparc
         */
        size = memblock_align_up(size, align);

        found = memblock_find_base(size, align, max_addr);
        if (found != MEMBLOCK_ERROR &&
            memblock_add_region(&memblock.reserved, found, size) >= 0)
                return found;

        return 0;
}

phys_addr_t __init memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
{
        phys_addr_t alloc;

        alloc = __memblock_alloc_base(size, align, max_addr);

        if (alloc == 0)
                panic("ERROR: Failed to allocate 0x%llx bytes below 0x%llx.\n",
                      (unsigned long long) size, (unsigned long long) max_addr);

        return alloc;
}

phys_addr_t __init memblock_alloc(phys_addr_t size, phys_addr_t align)
{
        return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
}


/*
 * Additional node-local allocators. Search for node memory is bottom up
 * and walks memblock regions within that node bottom-up as well, but allocation
 * within an memblock region is top-down.
 */

phys_addr_t __weak __init memblock_nid_range(phys_addr_t start, phys_addr_t end, int *nid)
{
        *nid = 0;

        return end;
}

static phys_addr_t __init memblock_alloc_nid_region(struct memblock_region *mp,
                                               phys_addr_t size,
                                               phys_addr_t align, int nid)
{
        phys_addr_t start, end;

        start = mp->base;
        end = start + mp->size;

        start = memblock_align_up(start, align);
        while (start < end) {
                phys_addr_t this_end;
                int this_nid;

                this_end = memblock_nid_range(start, end, &this_nid);
                if (this_nid == nid) {
                        phys_addr_t ret = memblock_find_region(start, this_end, size, align);
                        if (ret != MEMBLOCK_ERROR &&
                            memblock_add_region(&memblock.reserved, ret, size) >= 0)
                                return ret;
                }
                start = this_end;
        }

        return MEMBLOCK_ERROR;
}

phys_addr_t __init memblock_alloc_nid(phys_addr_t size, phys_addr_t align, int nid)
{
        struct memblock_type *mem = &memblock.memory;
        int i;

        BUG_ON(0 == size);

        /* We align the size to limit fragmentation. Without this, a lot of
         * small allocs quickly eat up the whole reserve array on sparc
         */
        size = memblock_align_up(size, align);

        /* We do a bottom-up search for a region with the right
         * nid since that's easier considering how memblock_nid_range()
         * works
         */
        for (i = 0; i < mem->cnt; i++) {
                phys_addr_t ret = memblock_alloc_nid_region(&mem->regions[i],
                                               size, align, nid);
                if (ret != MEMBLOCK_ERROR)
                        return ret;
        }

        return memblock_alloc(size, align);
}

/* You must call memblock_analyze() before this. */
phys_addr_t __init memblock_phys_mem_size(void)
{
        return memblock.memory_size;
}

phys_addr_t memblock_end_of_DRAM(void)
{
        int idx = memblock.memory.cnt - 1;

        return (memblock.memory.regions[idx].base + memblock.memory.regions[idx].size);
}

/* You must call memblock_analyze() after this. */
void __init memblock_enforce_memory_limit(phys_addr_t memory_limit)
{
        unsigned long i;
        phys_addr_t limit;
        struct memblock_region *p;

        if (!memory_limit)
                return;

        /* Truncate the memblock regions to satisfy the memory limit. */
        limit = memory_limit;
        for (i = 0; i < memblock.memory.cnt; i++) {
                if (limit > memblock.memory.regions[i].size) {
                        limit -= memblock.memory.regions[i].size;
                        continue;
                }

                memblock.memory.regions[i].size = limit;
                memblock.memory.cnt = i + 1;
                break;
        }

        memory_limit = memblock_end_of_DRAM();

        /* And truncate any reserves above the limit also. */
        for (i = 0; i < memblock.reserved.cnt; i++) {
                p = &memblock.reserved.regions[i];

                if (p->base > memory_limit)
                        p->size = 0;
                else if ((p->base + p->size) > memory_limit)
                        p->size = memory_limit - p->base;

                if (p->size == 0) {
                        memblock_remove_region(&memblock.reserved, i);
                        i--;
                }
        }
}

static int memblock_search(struct memblock_type *type, phys_addr_t addr)
{
        unsigned int left = 0, right = type->cnt;

        do {
                unsigned int mid = (right + left) / 2;

                if (addr < type->regions[mid].base)
                        right = mid;
                else if (addr >= (type->regions[mid].base +
                                  type->regions[mid].size))
                        left = mid + 1;
                else
                        return mid;
        } while (left < right);
        return -1;
}

int __init memblock_is_reserved(phys_addr_t addr)
{
        return memblock_search(&memblock.reserved, addr) != -1;
}

int memblock_is_memory(phys_addr_t addr)
{
        return memblock_search(&memblock.memory, addr) != -1;
}

int memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
{
        int idx = memblock_search(&memblock.reserved, base);

        if (idx == -1)
                return 0;
        return memblock.reserved.regions[idx].base <= base &&
                (memblock.reserved.regions[idx].base +
                 memblock.reserved.regions[idx].size) >= (base + size);
}

int memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
{
        return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
}


void __init memblock_set_current_limit(phys_addr_t limit)
{
        memblock.current_limit = limit;
}

static void memblock_dump(struct memblock_type *region, char *name)
{
        unsigned long long base, size;
        int i;

        pr_info(" %s.cnt  = 0x%lx\n", name, region->cnt);

        for (i = 0; i < region->cnt; i++) {
                base = region->regions[i].base;
                size = region->regions[i].size;

                pr_info(" %s[0x%x]\t0x%016llx - 0x%016llx, 0x%llx bytes\n",
                    name, i, base, base + size - 1, size);
        }
}

void memblock_dump_all(void)
{
        if (!memblock_debug)
                return;

        pr_info("MEMBLOCK configuration:\n");
        pr_info(" memory size = 0x%llx\n", (unsigned long long)memblock.memory_size);

        memblock_dump(&memblock.memory, "memory");
        memblock_dump(&memblock.reserved, "reserved");
}

void __init memblock_analyze(void)
{
        int i;

        /* Check marker in the unused last array entry */
        WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
                != (phys_addr_t)RED_INACTIVE);
        WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
                != (phys_addr_t)RED_INACTIVE);

        memblock.memory_size = 0;

        for (i = 0; i < memblock.memory.cnt; i++)
                memblock.memory_size += memblock.memory.regions[i].size;

        /* We allow resizing from there */
        memblock_can_resize = 1;
}

void __init memblock_init(void)
{
        /* Hookup the initial arrays */
        memblock.memory.regions = memblock_memory_init_regions;
        memblock.memory.max             = INIT_MEMBLOCK_REGIONS;
        memblock.reserved.regions       = memblock_reserved_init_regions;
        memblock.reserved.max   = INIT_MEMBLOCK_REGIONS;

        /* Write a marker in the unused last array entry */
        memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
        memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;

        /* Create a dummy zero size MEMBLOCK which will get coalesced away later.
         * This simplifies the memblock_add() code below...
         */
        memblock.memory.regions[0].base = 0;
        memblock.memory.regions[0].size = 0;
        memblock.memory.cnt = 1;

        /* Ditto. */
        memblock.reserved.regions[0].base = 0;
        memblock.reserved.regions[0].size = 0;
        memblock.reserved.cnt = 1;

        memblock.current_limit = MEMBLOCK_ALLOC_ANYWHERE;
}

static int __init early_memblock(char *p)
{
        if (p && strstr(p, "debug"))
                memblock_debug = 1;
        return 0;
}
early_param("memblock", early_memblock);