Re: [PATCH v4] zone_reclaim is always 0 by default

[Mel Gorman <mel@csn.ul.ie>]

On Tue, Jun 09, 2009 at 04:55:07AM -0500, Robin Holt wrote:
> On Mon, Jun 08, 2009 at 12:50:48PM +0100, Mel Gorman wrote:
> 
> Let me start by saying I agree completely with everything you wrote and
> still disagree with this patch, but was willing to compromise and work
> around this for our upcoming x86_64 machine by putting a "value add"
> into our packaging of adding a sysctl that turns reclaim back on.
> 

To be honest, I'm more leaning towards a NACK than an ACK on this one. I
don't support enough NUMA machines to feel strongly enough about it but
unconditionally setting zone_reclaim_mode to 0 on x86-64 just because i7's
might be there seems ill-advised to me and will have other consequences for
existing more traditional x86-64 NUMA machines.

> ...
> > > Index: b/arch/powerpc/include/asm/topology.h
> > > ===================================================================
> > > --- a/arch/powerpc/include/asm/topology.h
> > > +++ b/arch/powerpc/include/asm/topology.h
> > > @@ -10,6 +10,12 @@ struct device_node;
> > >  
> > >  #include <asm/mmzone.h>
> > >  
> > > +/*
> > > + * Distance above which we begin to use zone reclaim
> > > + */
> > > +#define RECLAIM_DISTANCE 20
> > > +
> > > +
> > 
> > Where is the ia-64-specific modifier to RECAIM_DISTANCE?
> 
> It was already defined as 15 in arch/ia64/include/asm/topology.h
> 

/me slaps self

thanks

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