Messages in this thread | | | Date | Mon, 3 Jan 2011 08:58:15 -0500 | From | Ted Ts'o <> | Subject | Re: Should we be using unlikely() around tests of GFP_ZERO? |
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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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