Re: [RFC PATCH v3 4/4] arm64:numa: adding numa support for arm64 platforms.

[Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>]

On Tuesday 06 January 2015 14:55:53 Ganapatrao Kulkarni wrote:
> On Sat, Jan 3, 2015 at 2:40 AM, Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org> wrote:
> >> +int dt_get_cpu_node_id(int cpu)
> >> +{
> >> +     struct device_node *dn = NULL;
> >> +
> >> +     while ((dn = of_find_node_by_type(dn, "cpu"))) {
> >> +             const u32 *cell;
> >> +             u64 hwid;
> >> +
> >> +             /*
> >> +              * A cpu node with missing "reg" property is
> >> +              * considered invalid to build a cpu_logical_map
> >> +              * entry.
> >> +              */
> >> +             cell = of_get_property(dn, "reg", NULL);
> >> +             if (!cell) {
> >> +                     pr_err("%s: missing reg property\n", dn->full_name);
> >> +                     return default_nid;
> >> +             }
> >> +             hwid = of_read_number(cell, of_n_addr_cells(dn));
> >> +
> >> +             if (cpu_logical_map(cpu) == hwid)
> >> +             return of_node_to_nid_single(dn);
> >> +     }
> >> +     return NUMA_NO_NODE;
> >> +}
> >> +EXPORT_SYMBOL(dt_get_cpu_node_id);
> >
> > Maybe just expose a function to the device node for a CPU ID here, and
> > expect callers to use of_node_to_nid?
> shall i make this wrapper function in dt_numa.c, which will use
> functions _of_node_to_nid and  _of_cpu_to_node(cpu)

Yes, I guess that would work.

> And,  this function can be a weak function in numa.c which returns 0.

No, please don't use weak functions. You can either use IS_ENABLED()
tricks to remove function calls at compile-time, or in the header
file provide an inline function as an alternative to the extern
declaration, based on a configuration symbol.

	Arnd
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