Re: [PATCH 00/25] Cleanup and optimise the page allocator V5

From: Mel Gorman
Date: Mon Mar 23 2009 - 10:59:34 EST


On Mon, Mar 23, 2009 at 09:30:26AM -0400, Christoph Lameter wrote:
> On Mon, 23 Mar 2009, Mel Gorman wrote:
>
> > This came up again. There was some evidence when it was introduced that
> > it worked and micro-benchmarks can show it to be of some use. It's
> > not-obvious-enough that I'd be wary of deleting it.
>
> Certainly there is some minimal benefit. But maybe that benefit will
> vanish if you drop the doubly linked list?
>

Extremely difficult to tell. It only makes a difference if you are not
over a cache-line boundary using a singly linked list. If the structure
is within a cache-line boundary with either single or double linked
lists, it probably makes no measurable difference.

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