Re: [PATCH 2/6] change alloc function in pcpu_alloc_pages

From: Mel Gorman
Date: Tue Apr 20 2010 - 11:05:47 EST


On Tue, Apr 20, 2010 at 07:27:09AM +0900, Tejun Heo wrote:
> Hello, Christoph.
>
> On 04/20/2010 02:38 AM, Christoph Lameter wrote:
> > alloc_pages_exact_node results in more confusion because it does suggest
> > that fallback to other nodes is not allowed.
>
> I can't see why alloc_pages_exact_node() exists at all. It's in the
> mainline and if you look at the difference between alloc_pages_node()
> and alloc_pages_exact_node(), it's almost silly. :-(
>

alloc_pages_exact_node() avoids a branch in a hot path that is checking for
something the caller already knows. That's the reason it exists.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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