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Commit b3199c02 authored by Rusty Russell's avatar Rusty Russell
Browse files

cpumask: switch over to cpu_online/possible/active/present_mask: core 



Impact: cleanup

This implements the obsolescent cpu_online_map in terms of
cpu_online_mask, rather than the other way around.  Same for the other
maps.

The documentation comments are also updated to refer to _mask rather
than _map.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarMike Travis <travis@sgi.com>
parent cb78a0ce

include/linux/cpumask.h

+29 −46
Original line number Diff line number Diff line
@@ -416,65 +416,54 @@ int __next_cpu_nr(int n, const cpumask_t *srcp); 


/*

 * The following particular system cpumasks and operations manage

 * possible, present, active and online cpus.  Each of them is a fixed size

 * bitmap of size NR_CPUS.

 * possible, present, active and online cpus.

 *

 *  #ifdef CONFIG_HOTPLUG_CPU

 *     cpu_possible_map - has bit 'cpu' set iff cpu is populatable

 *     cpu_present_map  - has bit 'cpu' set iff cpu is populated

 *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler

 *     cpu_active_map   - has bit 'cpu' set iff cpu available to migration

 *  #else

 *     cpu_possible_map - has bit 'cpu' set iff cpu is populated

 *     cpu_present_map  - copy of cpu_possible_map

 *     cpu_online_map   - has bit 'cpu' set iff cpu available to scheduler

 *  #endif

 *     cpu_possible_mask- has bit 'cpu' set iff cpu is populatable

 *     cpu_present_mask - has bit 'cpu' set iff cpu is populated

 *     cpu_online_mask  - has bit 'cpu' set iff cpu available to scheduler

 *     cpu_active_mask  - has bit 'cpu' set iff cpu available to migration

 *

 *  In either case, NR_CPUS is fixed at compile time, as the static

 *  size of these bitmaps.  The cpu_possible_map is fixed at boot

 *  time, as the set of CPU id's that it is possible might ever

 *  be plugged in at anytime during the life of that system boot.

 *  The cpu_present_map is dynamic(*), representing which CPUs

 *  are currently plugged in.  And cpu_online_map is the dynamic

 *  subset of cpu_present_map, indicating those CPUs available

 *  for scheduling.

 *  If !CONFIG_HOTPLUG_CPU, present == possible, and active == online.

 *

 *  If HOTPLUG is enabled, then cpu_possible_map is forced to have

 *  The cpu_possible_mask is fixed at boot time, as the set of CPU id's

 *  that it is possible might ever be plugged in at anytime during the

 *  life of that system boot.  The cpu_present_mask is dynamic(*),

 *  representing which CPUs are currently plugged in.  And

 *  cpu_online_mask is the dynamic subset of cpu_present_mask,

 *  indicating those CPUs available for scheduling.

 *

 *  If HOTPLUG is enabled, then cpu_possible_mask is forced to have

 *  all NR_CPUS bits set, otherwise it is just the set of CPUs that

 *  ACPI reports present at boot.

 *

 *  If HOTPLUG is enabled, then cpu_present_map varies dynamically,

 *  If HOTPLUG is enabled, then cpu_present_mask varies dynamically,

 *  depending on what ACPI reports as currently plugged in, otherwise

 *  cpu_present_map is just a copy of cpu_possible_map.

 *  cpu_present_mask is just a copy of cpu_possible_mask.

 *

 *  (*) Well, cpu_present_map is dynamic in the hotplug case.  If not

 *      hotplug, it's a copy of cpu_possible_map, hence fixed at boot.

 *  (*) Well, cpu_present_mask is dynamic in the hotplug case.  If not

 *      hotplug, it's a copy of cpu_possible_mask, hence fixed at boot.

 *

 * Subtleties:

 * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode

 *    assumption that their single CPU is online.  The UP

 *    cpu_{online,possible,present}_maps are placebos.  Changing them

 *    cpu_{online,possible,present}_masks are placebos.  Changing them

 *    will have no useful affect on the following num_*_cpus()

 *    and cpu_*() macros in the UP case.  This ugliness is a UP

 *    optimization - don't waste any instructions or memory references

 *    asking if you're online or how many CPUs there are if there is

 *    only one CPU.

 * 2) Most SMP arch's #define some of these maps to be some

 *    other map specific to that arch.  Therefore, the following

 *    must be #define macros, not inlines.  To see why, examine

 *    the assembly code produced by the following.  Note that

 *    set1() writes phys_x_map, but set2() writes x_map:

 *        int x_map, phys_x_map;

 *        #define set1(a) x_map = a

 *        inline void set2(int a) { x_map = a; }

 *        #define x_map phys_x_map

 *        main(){ set1(3); set2(5); }

 */



extern cpumask_t cpu_possible_map;

extern cpumask_t cpu_online_map;

extern cpumask_t cpu_present_map;

extern cpumask_t cpu_active_map;

extern const struct cpumask *const cpu_possible_mask;

extern const struct cpumask *const cpu_online_mask;

extern const struct cpumask *const cpu_present_mask;

extern const struct cpumask *const cpu_active_mask;



/* These strip const, as traditionally they weren't const. */

#define cpu_possible_map	(*(cpumask_t *)cpu_possible_mask)

#define cpu_online_map		(*(cpumask_t *)cpu_online_mask)

#define cpu_present_map		(*(cpumask_t *)cpu_present_mask)

#define cpu_active_map		(*(cpumask_t *)cpu_active_mask)



#if NR_CPUS > 1

#define num_online_cpus()	cpus_weight_nr(cpu_online_map)
@@ -1058,12 +1047,6 @@ static inline void free_bootmem_cpumask_var(cpumask_var_t mask) 
}

#endif /* CONFIG_CPUMASK_OFFSTACK */



/* The pointer versions of the maps, these will become the primary versions. */

#define cpu_possible_mask ((const struct cpumask *)&cpu_possible_map)

#define cpu_online_mask ((const struct cpumask *)&cpu_online_map)

#define cpu_present_mask ((const struct cpumask *)&cpu_present_map)

#define cpu_active_mask ((const struct cpumask *)&cpu_active_map)



/* It's common to want to use cpu_all_mask in struct member initializers,

 * so it has to refer to an address rather than a pointer. */

extern const DECLARE_BITMAP(cpu_all_bits, NR_CPUS);

kernel/cpu.c

+23 −26
Original line number Diff line number Diff line
@@ -15,30 +15,8 @@ 
#include <linux/stop_machine.h>

#include <linux/mutex.h>



/*

 * Represents all cpu's present in the system

 * In systems capable of hotplug, this map could dynamically grow

 * as new cpu's are detected in the system via any platform specific

 * method, such as ACPI for e.g.

 */

cpumask_t cpu_present_map __read_mostly;

EXPORT_SYMBOL(cpu_present_map);



/*

 * Represents all cpu's that are currently online.

 */

cpumask_t cpu_online_map __read_mostly;

EXPORT_SYMBOL(cpu_online_map);



#ifdef CONFIG_INIT_ALL_POSSIBLE

cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;

#else

cpumask_t cpu_possible_map __read_mostly;

#endif

EXPORT_SYMBOL(cpu_possible_map);



#ifdef CONFIG_SMP

/* Serializes the updates to cpu_online_map, cpu_present_map */

/* Serializes the updates to cpu_online_mask, cpu_present_mask */

static DEFINE_MUTEX(cpu_add_remove_lock);



static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
@@ -65,8 +43,6 @@ void __init cpu_hotplug_init(void) 
	cpu_hotplug.refcount = 0;

}



cpumask_t cpu_active_map;



#ifdef CONFIG_HOTPLUG_CPU



void get_online_cpus(void)
@@ -97,7 +73,7 @@ EXPORT_SYMBOL_GPL(put_online_cpus); 


/*

 * The following two API's must be used when attempting

 * to serialize the updates to cpu_online_map, cpu_present_map.

 * to serialize the updates to cpu_online_mask, cpu_present_mask.

 */

void cpu_maps_update_begin(void)

{
@@ -503,3 +479,24 @@ EXPORT_SYMBOL_GPL(cpu_bit_bitmap); 


const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;

EXPORT_SYMBOL(cpu_all_bits);



#ifdef CONFIG_INIT_ALL_POSSIBLE

static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly

	= CPU_BITS_ALL;

#else

static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly;

#endif

const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits);

EXPORT_SYMBOL(cpu_possible_mask);



static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly;

const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits);

EXPORT_SYMBOL(cpu_online_mask);



static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly;

const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits);

EXPORT_SYMBOL(cpu_present_mask);



static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly;

const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits);

EXPORT_SYMBOL(cpu_active_mask);