Re: [PATCH 1/5] x86: Change size of node ids from u8 to u16 fixup

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Jan 18, 2008 8:36 PM, David Rientjes <rientjes@google.com> wrote:
> On Fri, 18 Jan 2008, Yinghai Lu wrote:
>
> > > +#if MAX_NUMNODES > 256
> > > +typedef u16 numanode_t;
> > > +#else
> > > +typedef u8 numanode_t;
> > > +#endif
> > > +
> > >  #endif /* _LINUX_NUMA_H */
> >
> > that is wrong, you can not change pxm_to_node_map from int to u8 or u16.
> >
>
> Yeah, NID_INVAL is negative so no unsigned type will work here,
> unfortunately.  And that reduces the intended savings of your change since
> the smaller type can only be used with a smaller CONFIG_NODES_SHIFT.
>
> > int acpi_map_pxm_to_node(int pxm)
> > {
> >         int node = pxm_to_node_map[pxm];
> >
> >         if (node < 0){
> >                 if (nodes_weight(nodes_found_map) >= MAX_NUMNODES)
> >                         return NID_INVAL;
> >                 node = first_unset_node(nodes_found_map);
> >                 __acpi_map_pxm_to_node(pxm, node);
> >                 node_set(node, nodes_found_map);
> >         }
> >
> >         return node;
> > }
> >
> > node will will be always 255 or 65535
> >
>
> Right.
>
> > please keep that to int.
> >
> > I got
> > SART: PXM 0 -> APIC 0 -> Node 255
> > SART: PXM 0 -> APIC 1 -> Node 255
> > SART: PXM 1 -> APIC 2 -> Node 255
> > SART: PXM 1 -> APIC 3 -> Node 255
> >
>
> I assume this is a typo and those proximity mappings are actually from the
> SRAT.

SRAT for processor only have
PXM and APIC id. setup_node(pxm) will get node id for pxm, start from 0...

> >         if (node < 0){
> >                 if (nodes_weight(nodes_found_map) >= MAX_NUMNODES)
> >                         return NID_INVAL;
> >                 node = first_unset_node(nodes_found_map);
> >                 __acpi_map_pxm_to_node(pxm, node);
> >                 node_set(node, nodes_found_map);
> >         }

YH