Re: why swap at all?

[John Bradford]

Quote from William Lee Irwin III <wli@xxxxxxxxxxxxxx>:
> Quote from William Lee Irwin III <wli@xxxxxxxxxxxxxx>:
> >> So you can move userspace pages out of ZONE_DMA as-needed.
> 
> On Tue, Jun 01, 2004 at 09:50:08AM +0100, John Bradford wrote:
> > But how does that improve performance before untouched RAM, (496788 in this
> > example), is exhausted?
> > In normal use, (almost always CPU bound), I've honestly never noticed any
> > performance gain from having swap configured.  I must admit I haven't put
> > a lot of effort recently in to looking at this, but I have never been able
> > to reproduce these 'swap increases performance even with untouched RAM'
> > claims.
> 
> Because ZONE_DMA, the lower 16MB is not all of RAM.

Ah, OK, this isn't really my area of expertise so maybe this is a stupid, (for
LKML), question, but can we only migrate data from low RAM via swap!?

Also, surely this is only relevant to X86 architectures?

John.
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