Messages in this thread | | | Date | Sat, 22 May 2004 01:52:36 -0700 | From | William Lee Irwin III <> | Subject | Re: slab redzoning |
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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.
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