Re: [PATCH] x86_64 - UV fix for memory-only blades

[Jack Steiner <steiner@sgi.com>]

On Tue, May 19, 2009 at 08:13:05AM -0700, Yinghai Lu wrote:
> Jack Steiner wrote:
> > Fix an endcase in handling UV blades that have memory
> > but no cpus. The calculation of the highest blade number
> > failed to handle these blades if they appear last in the
> > configuration.
> > 
> > Signed-off-by: Jack Steiner <steiner@sgi.com>
> > 
> > ---
> >  arch/x86/kernel/apic/x2apic_uv_x.c |    1 +
> >  1 file changed, 1 insertion(+)
> > 
> > Index: linux/arch/x86/kernel/apic/x2apic_uv_x.c
> > ===================================================================
> > --- linux.orig/arch/x86/kernel/apic/x2apic_uv_x.c	2009-05-15 12:00:59.000000000 -0500
> > +++ linux/arch/x86/kernel/apic/x2apic_uv_x.c	2009-05-15 14:38:16.000000000 -0500
> > @@ -632,6 +632,7 @@ void __init uv_system_init(void)
> >  		pnode = (paddr >> m_val) & pnode_mask;
> >  		blade = boot_pnode_to_blade(pnode);
> >  		uv_node_to_blade[nid] = blade;
> > +		max_pnode = max(pnode, max_pnode);
> >  	}
> >  
> >  	map_gru_high(max_pnode);
> 
> node_possible_map should already include nodes with memory and without memory already.
> 
> maybe you could skip max_pnode calculating in the loop.

Terms related to nodes are grossly overloaded.

"pnode" is only loosely related to a node. It is a physical node number that
is a hardware-thing. For example, it is possible to have a 1 node system with a max_pnode
of 128. 

pnodes are used only in the UV infrastructure - they have no generic meaning nor would they apply
to any other platform.


--- jack