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    Subject[PATCH 04/43] memblock: Implement memblock_is_memory and memblock_is_region_memory
    Date
    To make it fast, we steal ARM's binary search for memblock_is_memory()
    and we use that to also the replace existing implementation of
    memblock_is_reserved().

    Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    ---
    include/linux/memblock.h | 2 ++
    mm/memblock.c | 42 ++++++++++++++++++++++++++++++++++--------
    2 files changed, 36 insertions(+), 8 deletions(-)

    diff --git a/include/linux/memblock.h b/include/linux/memblock.h
    index 4b69313..47bceb1 100644
    --- a/include/linux/memblock.h
    +++ b/include/linux/memblock.h
    @@ -56,6 +56,8 @@ extern u64 __init __memblock_alloc_base(u64 size,
    extern u64 __init memblock_phys_mem_size(void);
    extern u64 memblock_end_of_DRAM(void);
    extern void __init memblock_enforce_memory_limit(u64 memory_limit);
    +extern int memblock_is_memory(u64 addr);
    +extern int memblock_is_region_memory(u64 base, u64 size);
    extern int __init memblock_is_reserved(u64 addr);
    extern int memblock_is_region_reserved(u64 base, u64 size);
    extern int memblock_find(struct memblock_region *res);
    diff --git a/mm/memblock.c b/mm/memblock.c
    index 6f407cc..aa88c62 100644
    --- a/mm/memblock.c
    +++ b/mm/memblock.c
    @@ -487,17 +487,43 @@ void __init memblock_enforce_memory_limit(u64 memory_limit)
    }
    }

    +static int memblock_search(struct memblock_type *type, u64 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(u64 addr)
    {
    - int i;
    + return memblock_search(&memblock.reserved, addr) != -1;
    +}

    - for (i = 0; i < memblock.reserved.cnt; i++) {
    - u64 upper = memblock.reserved.regions[i].base +
    - memblock.reserved.regions[i].size - 1;
    - if ((addr >= memblock.reserved.regions[i].base) && (addr <= upper))
    - return 1;
    - }
    - return 0;
    +int memblock_is_memory(u64 addr)
    +{
    + return memblock_search(&memblock.memory, addr) != -1;
    +}
    +
    +int memblock_is_region_memory(u64 base, u64 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(u64 base, u64 size)
    --
    1.7.0.4


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