x86: restore pda nodenumber field

  * Restore the nodenumber field in the x86_64 pda.  This field is slightly
    different than the x86_cpu_to_node_map mainly because it's a static
    indication of which node the cpu is on while the cpu to node map is a
    dyanamic mapping that may get reset if the cpu goes offline.  This also
    simplifies the numa_node_id() macro.

For inclusion into sched-devel/latest tree.

Based on:
	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
    +   sched-devel/latest  .../mingo/linux-2.6-sched-devel.git
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/setup.c

@@ -32,6 +32,7 @@ EXPORT_EARLY_PER_CPU_SYMBOL(x86_bios_cpu_apicid);
 #if defined(CONFIG_NUMA) && defined(CONFIG_X86_64)
 #define	X86_64_NUMA	1
 
+/* map cpu index to node index */
 DEFINE_EARLY_PER_CPU(int, x86_cpu_to_node_map, NUMA_NO_NODE);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_node_map);
 #endif
@@ -155,6 +156,9 @@ void __cpuinit numa_set_node(int cpu, int node)
 {
 	int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);
 
+	if (node != NUMA_NO_NODE)
+		cpu_pda(cpu)->nodenumber = node;
+
 	if (cpu_to_node_map)
 		cpu_to_node_map[cpu] = node;
 

include/asm-x86/pda.h

@@ -22,6 +22,7 @@ struct x8664_pda {
 					   offset 40!!! */
 #endif
 	char *irqstackptr;
+	int nodenumber;			/* number of current node */
 	unsigned int __softirq_pending;
 	unsigned int __nmi_count;	/* number of NMI on this CPUs */
 	short mmu_state;

include/asm-x86/topology.h

@@ -66,7 +66,7 @@ extern cpumask_t node_to_cpumask_map[];
 DECLARE_EARLY_PER_CPU(int, x86_cpu_to_node_map);
 
 /* Returns the number of the current Node. */
-#define numa_node_id()	(per_cpu(x86_cpu_to_node_map, raw_smp_processor_id()))
+#define numa_node_id()		read_pda(nodenumber)
 
 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
 extern int cpu_to_node(int cpu);