Re: How kernel applies LRU to swap out physical pages?

From: Peter Zijlstra
Date: Tue Nov 11 2008 - 06:33:54 EST


On Tue, 2008-11-11 at 18:56 +0900, KOSAKI Motohiro wrote:
> > On Tue, 2008-11-11 at 16:22 +0800, Pan ruochen wrote:
> > > Hi All,
> > > I'm reading the linux kernel 2.6.14. But can't understand how LRU algorithm
> > > is applied to page swapping. what is the 'USED' of LRU referred to? The
> > > reference counter which the page is mapped by processes, or the frequency that
> > > CPU reads/writes in the page. In common sense, the LRU algorithm will be more
> > > optimal for the second case. But it depends on CPU capability.
> > > I will be very appreciated if somebody can explain that in details.
> >
> > We don't actually use LRU but something like CLOCK.

FWIW in case you hadn't found it yet:

http://en.wikipedia.org/wiki/Page_replacement_algorithm

is a fairly decent page on the subject.
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