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    SubjectRe: slab redzoning
    William Lee Irwin III wrote:
    >> It returns a false positive when size + 3*BYTES_PER_WORD == 2**n, e.g.
    >> size == 16373. Here, fls(size - 1) == 13, but fls(size - 1 + 12) == 13
    >> while size - 1 + 12 == 16384, where we'd want the check to fail.

    On Sat, May 22, 2004 at 10:43:47AM +0200, Manfred Spraul wrote:
    > No, 16373 must fail: After adding 12 bytes the object size would be
    > 16385, which would mean an order==3 allocation.
    > And 16372 must succeed: 16384 is still an order==2 allocation.
    > The idea is that there shouldn't be an allocation order increase due to
    > redzoning, and afaics that doesn't happen, except between 4082 and 4095
    > bytes.

    Yes. While you've corrected the one-offs in my post (arithmetic is boring,
    we have machines to do that for us now), 16372 remains in question as
    far as I can tell.


    -- wli
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