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

On Tuesday 06 January 2015 14:55:53 Ganapatrao Kulkarni wrote:

On Sat, Jan 3, 2015 at 2:40 AM, Arnd Bergmann [off-list ref] wrote:

quoted

quoted

+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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