Commit 14adf855 authored by Chuck Ebbert's avatar Chuck Ebbert Committed by Ingo Molnar
Browse files

x86: move prefill_possible_map calling early, fix, V2 



Commit 4a701737 ("x86: move prefill_possible_map calling early, fix")
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.

Fix this correctly 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: default avatarChuck Ebbert <cebbert@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 69d45dd1

arch/x86/kernel/smpboot.c

+31 −31
Original line number Diff line number Diff line
@@ -1261,39 +1261,8 @@ void __init native_smp_cpus_done(unsigned int max_cpus) 
	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
@@ -1340,6 +1309,37 @@ __init void prefill_possible_map(void) 
	nr_cpu_ids = possible;

}



#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 __init int setup_additional_cpus(char *s)

{

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

}

early_param("additional_cpus", setup_additional_cpus);



static void __ref remove_cpu_from_maps(int cpu)

{

	cpu_clear(cpu, cpu_online_map);

include/asm-x86/smp.h

+3 −5
Original line number Diff line number Diff line
@@ -141,6 +141,8 @@ void play_dead_common(void); 
void native_send_call_func_ipi(cpumask_t mask);

void native_send_call_func_single_ipi(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)
@@ -149,15 +151,11 @@ static inline int num_booting_cpus(void) 
{

	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

#endif /* CONFIG_SMP */



extern unsigned disabled_cpus __cpuinitdata;

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