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    Subject[patch 3/4] mm: bootmem: drop superfluous range check when freeing pages in bulk
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    The area node_bootmem_map represents is aligned to BITS_PER_LONG, and
    all bits in any aligned word of that map valid. When the represented
    area extends beyond the end of the node, the non-existant pages will
    be marked as reserved.

    As a result, when freeing a page block, doing an explicit range check
    for whether that block is within the node's range is redundant as the
    bitmap is consulted anyway to see whether all pages in the block are
    unreserved.

    Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
    ---
    mm/bootmem.c | 2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)

    diff --git a/mm/bootmem.c b/mm/bootmem.c
    index 3e6f152..1aea171 100644
    --- a/mm/bootmem.c
    +++ b/mm/bootmem.c
    @@ -197,7 +197,7 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
    idx = start - bdata->node_min_pfn;
    vec = ~map[idx / BITS_PER_LONG];

    - if (aligned && vec == ~0UL && start + BITS_PER_LONG <= end) {
    + if (aligned && vec == ~0UL) {
    int order = ilog2(BITS_PER_LONG);

    __free_pages_bootmem(pfn_to_page(start), order);
    --
    1.7.7.3


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