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Commit 34db18a0 authored by Amerigo Wang's avatar Amerigo Wang Committed by Linus Torvalds
Browse files

smp: move smp setup functions to kernel/smp.c 



Move setup_nr_cpu_ids(), smp_init() and some other SMP boot parameter
setup functions from init/main.c to kenrel/smp.c, saves some #ifdef
CONFIG_SMP.

Signed-off-by: default avatarWANG Cong <amwang@redhat.com>
Cc: Rakib Mullick <rakib.mullick@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fa9ee9c4

include/linux/smp.h

+2 −0
Original line number Diff line number Diff line
@@ -114,6 +114,8 @@ int on_each_cpu(smp_call_func_t func, void *info, int wait); 
void smp_prepare_boot_cpu(void);



extern unsigned int setup_max_cpus;

extern void __init setup_nr_cpu_ids(void);

extern void __init smp_init(void);



#else /* !SMP */

init/main.c

+1 −89
Original line number Diff line number Diff line
@@ -129,63 +129,6 @@ static char *static_command_line; 
static char *execute_command;

static char *ramdisk_execute_command;



#ifdef CONFIG_SMP

/* Setup configured maximum number of CPUs to activate */

unsigned int setup_max_cpus = NR_CPUS;

EXPORT_SYMBOL(setup_max_cpus);





/*

 * Setup routine for controlling SMP activation

 *

 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP

 * activation entirely (the MPS table probe still happens, though).

 *

 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer

 * greater than 0, limits the maximum number of CPUs activated in

 * SMP mode to <NUM>.

 */



void __weak arch_disable_smp_support(void) { }



static int __init nosmp(char *str)

{

	setup_max_cpus = 0;

	arch_disable_smp_support();



	return 0;

}



early_param("nosmp", nosmp);



/* this is hard limit */

static int __init nrcpus(char *str)

{

	int nr_cpus;



	get_option(&str, &nr_cpus);

	if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)

		nr_cpu_ids = nr_cpus;



	return 0;

}



early_param("nr_cpus", nrcpus);



static int __init maxcpus(char *str)

{

	get_option(&str, &setup_max_cpus);

	if (setup_max_cpus == 0)

		arch_disable_smp_support();



	return 0;

}



early_param("maxcpus", maxcpus);

#else

static const unsigned int setup_max_cpus = NR_CPUS;

#endif



/*

 * If set, this is an indication to the drivers that reset the underlying

 * device before going ahead with the initialization otherwise driver might
@@ -362,7 +305,7 @@ static int __init rdinit_setup(char *str) 
__setup("rdinit=", rdinit_setup);



#ifndef CONFIG_SMP



static const unsigned int setup_max_cpus = NR_CPUS;

#ifdef CONFIG_X86_LOCAL_APIC

static void __init smp_init(void)

{
@@ -374,37 +317,6 @@ static void __init smp_init(void) 


static inline void setup_nr_cpu_ids(void) { }

static inline void smp_prepare_cpus(unsigned int maxcpus) { }



#else



/* Setup number of possible processor ids */

int nr_cpu_ids __read_mostly = NR_CPUS;

EXPORT_SYMBOL(nr_cpu_ids);



/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */

static void __init setup_nr_cpu_ids(void)

{

	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;

}



/* Called by boot processor to activate the rest. */

static void __init smp_init(void)

{

	unsigned int cpu;



	/* FIXME: This should be done in userspace --RR */

	for_each_present_cpu(cpu) {

		if (num_online_cpus() >= setup_max_cpus)

			break;

		if (!cpu_online(cpu))

			cpu_up(cpu);

	}



	/* Any cleanup work */

	printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());

	smp_cpus_done(setup_max_cpus);

}



#endif



/*

kernel/smp.c

+81 −0
Original line number Diff line number Diff line
@@ -604,6 +604,87 @@ void ipi_call_unlock_irq(void) 
}

#endif /* USE_GENERIC_SMP_HELPERS */



/* Setup configured maximum number of CPUs to activate */

unsigned int setup_max_cpus = NR_CPUS;

EXPORT_SYMBOL(setup_max_cpus);





/*

 * Setup routine for controlling SMP activation

 *

 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP

 * activation entirely (the MPS table probe still happens, though).

 *

 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer

 * greater than 0, limits the maximum number of CPUs activated in

 * SMP mode to <NUM>.

 */



void __weak arch_disable_smp_support(void) { }



static int __init nosmp(char *str)

{

	setup_max_cpus = 0;

	arch_disable_smp_support();



	return 0;

}



early_param("nosmp", nosmp);



/* this is hard limit */

static int __init nrcpus(char *str)

{

	int nr_cpus;



	get_option(&str, &nr_cpus);

	if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)

		nr_cpu_ids = nr_cpus;



	return 0;

}



early_param("nr_cpus", nrcpus);



static int __init maxcpus(char *str)

{

	get_option(&str, &setup_max_cpus);

	if (setup_max_cpus == 0)

		arch_disable_smp_support();



	return 0;

}



early_param("maxcpus", maxcpus);



/* Setup number of possible processor ids */

int nr_cpu_ids __read_mostly = NR_CPUS;

EXPORT_SYMBOL(nr_cpu_ids);



/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */

void __init setup_nr_cpu_ids(void)

{

	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;

}



/* Called by boot processor to activate the rest. */

void __init smp_init(void)

{

	unsigned int cpu;



	/* FIXME: This should be done in userspace --RR */

	for_each_present_cpu(cpu) {

		if (num_online_cpus() >= setup_max_cpus)

			break;

		if (!cpu_online(cpu))

			cpu_up(cpu);

	}



	/* Any cleanup work */

	printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());

	smp_cpus_done(setup_max_cpus);

}



/*

 * Call a function on all processors.  May be used during early boot while

 * early_boot_irqs_disabled is set.  Use local_irq_save/restore() instead