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    SubjectRe: Should we be using unlikely() around tests of GFP_ZERO?
    On Mon, Jan 03, 2011 at 09:40:57AM +0200, Pekka Enberg wrote:
    > I guess the rationale here is that if you're going to take the hit of
    > memset() you can take the hit of unlikely() as well. We're optimizing
    > for hot call-sites that allocate a small amount of memory and
    > initialize everything themselves. That said, I don't think the
    > unlikely() annotation matters much either way and am for removing it
    > unless people object to that.

    I suspect for many slab caches, all of the slab allocations for a
    given slab cache type will have the GFP_ZERO flag passed. So maybe it
    would be more efficient to zap the entire page when it is pressed into
    service for a particular slab cache, so we can avoid needing to use
    memset on a per-object basis?

    - Ted


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