Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8b3b2955 authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
Browse files

adjust nosmp handling 



Especially when !CONFIG_HOTPLUG_CPU, avoid needlessy allocating resources for
CPUs that can never become available.

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 98c0d07c

init/main.c

+27 −15
Original line number Diff line number Diff line
@@ -132,20 +132,9 @@ 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 */

static unsigned int max_cpus = NR_CPUS;



/*

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

 * device before going ahead with the initialization otherwise driver might

 * rely on the BIOS and skip the reset operation.

 *

 * This is useful if kernel is booting in an unreliable environment.

 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been

 * skipped and devices will be in unknown state.

 */

unsigned int reset_devices;

EXPORT_SYMBOL(reset_devices);

static unsigned int __initdata max_cpus = NR_CPUS;



/*

 * Setup routine for controlling SMP activation
@@ -160,10 +149,10 @@ EXPORT_SYMBOL(reset_devices); 
static int __init nosmp(char *str)

{

	max_cpus = 0;

	return 1;

	return 0;

}



__setup("nosmp", nosmp);

early_param("nosmp", nosmp);



static int __init maxcpus(char *str)

{
@@ -172,6 +161,21 @@ static int __init maxcpus(char *str) 
}



__setup("maxcpus=", maxcpus);

#else

#define 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

 * rely on the BIOS and skip the reset operation.

 *

 * This is useful if kernel is booting in an unreliable environment.

 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been

 * skipped and devices will be in unknown state.

 */

unsigned int reset_devices;

EXPORT_SYMBOL(reset_devices);



static int __init set_reset_devices(char *str)

{
@@ -385,6 +389,10 @@ static void __init smp_init(void) 
{

	unsigned int cpu;



#ifndef CONFIG_HOTPLUG_CPU

	cpu_possible_map = cpu_present_map;

#endif



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

	for_each_present_cpu(cpu) {

		if (num_online_cpus() >= max_cpus)
@@ -529,6 +537,10 @@ asmlinkage void __init start_kernel(void) 
	setup_arch(&command_line);

	setup_command_line(command_line);

	unwind_setup();

#ifndef CONFIG_HOTPLUG_CPU

	if (max_cpus < 2)

		cpu_possible_map = cpu_online_map;

#endif

	setup_per_cpu_areas();

	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */