From: Chuck Ebbert <cebbert@redhat.com>
revert: x86: move prefill_possible_map calling early, fix
revert 4a7017370aa0a94a00ae5b5705e9169cdcae5fb8
This is the wrong fix: prefill_possible_map() needs to be available

even when CONFIG_HOTPLUG_CPU is not set. A followon patch will do that.
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
---
--- b/include/asm-x86/smp.h

+++ a/include/asm-x86/smp.h

@@ -116,6 +116,8 @@

 extern int __cpu_disable(void);

 extern void __cpu_die(unsigned int cpu);
+extern void prefill_possible_map(void);

+

 void smp_store_cpu_info(int id);

 #define cpu_physical_id(cpu)	per_cpu(x86_cpu_to_apicid, cpu)
@@ -124,15 +126,11 @@

 {

 	return cpus_weight(cpu_callout_map);

 }

-#endif /* CONFIG_SMP */

-

-#if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_CPU)

-extern void prefill_possible_map(void);

 #else

 static inline void prefill_possible_map(void)

 {

 }

+#endif /* CONFIG_SMP */

-#endif
 extern unsigned disabled_cpus __cpuinitdata;
--

From: Chuck Ebbert <cebbert@redhat.com>
x86: move prefill_possible_map calling early, fix, V2
fix:
Fix this by making prefill_possible_map() available even when

CONFIG_HOTPLUG_CPU is not set. The function is needed so that

the number of possible CPUs can be determined.
Tested on uniprocessor machine with CPU hotplug disabled.

From boot log:

Before: NR_CPUS: 512, nr_cpu_ids: 512, nr_node_ids 1

After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
---
Index: linux-2.6.26.noarch/arch/x86/kernel/smpboot.c

===================================================================

--- linux-2.6.26.noarch.orig/arch/x86/kernel/smpboot.c

+++ linux-2.6.26.noarch/arch/x86/kernel/smpboot.c

@@ -1254,39 +1254,8 @@ void __init native_smp_cpus_done(unsigne

 	check_nmi_watchdog();

 }
-#ifdef CONFIG_HOTPLUG_CPU

-

-static void remove_siblinginfo(int cpu)

-{

-	int sibling;

-	struct cpuinfo_x86 *c = &cpu_data(cpu);

-

-	for_each_cpu_mask_nr(sibling, per_cpu(cpu_core_map, cpu)) {

-		cpu_clear(cpu, per_cpu(cpu_core_map, sibling));

-		/*/

-		 * last thread sibling in this cpu core going down

-		 */

-		if (cpus_weight(per_cpu(cpu_sibling_map, cpu)) == 1)

-			cpu_data(sibling).booted_cores--;

-	}

-

-	for_each_cpu_mask_nr(sibling, per_cpu(cpu_sibling_map, cpu))

-		cpu_clear(cpu, per_cpu(cpu_sibling_map, sibling));

-	cpus_clear(per_cpu(cpu_sibling_map, cpu));

-	cpus_clear(per_cpu(cpu_core_map, cpu));

-	c->phys_proc_id = 0;

-	c->cpu_core_id = 0;

-	cpu_clear(cpu, cpu_sibling_setup_map);

-}

-

 static int additional_cpus __initdata = -1;
-static __init int setup_additional_cpus(char *s)

-{

-	return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;

-}

-early_param("additional_cpus", setup_additional_cpus);

-

 /*

  * cpu_possible_map should be static, it cannot change as cpu's

  * are onlined, or offlined. The reason is per-cpu data-structures

@@ -1336,6 +1305,37 @@ __init void prefill_possible_...
[ message continues ]

applied to tip/x86/core, thanks Chuck! Made it a single delta patch, to

ease backporting.
	Ingo

--