android_kernel_motorola_sm6225/include/linux/cpu.h
Avi Kivity 47e627bc8c [PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU
The following patchset allows a host with running virtual machines to be
suspended and, on at least a subset of the machines tested, resumed.  Note
that this is orthogonal to suspending and resuming an individual guest to a
file.

A side effect of implementing suspend/resume is that cpu hotplug is now
supported.  This should please the owners of big iron.

This patch:

KVM wants the cpu hotplug notifications, both for cpu hotplug itself, but more
commonly for host suspend/resume.

In order to avoid extensive #ifdefs, provide stubs when CONFIG_CPU_HOTPLUG is
not defined.

In all, we have four cases:

- UP: register and unregister stubbed out
- SMP+hotplug: full register and unregister
- SMP, no hotplug, core: register as __init, unregister stubbed
      (cpus are brought up during core initialization)
- SMP, no hotplug, module: register and unregister stubbed out
      (cpus cannot be brought up during module lifetime)

Signed-off-by: Avi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:40 -08:00

137 lines
3.8 KiB
C

/*
* include/linux/cpu.h - generic cpu definition
*
* This is mainly for topological representation. We define the
* basic 'struct cpu' here, which can be embedded in per-arch
* definitions of processors.
*
* Basic handling of the devices is done in drivers/base/cpu.c
* and system devices are handled in drivers/base/sys.c.
*
* CPUs are exported via sysfs in the class/cpu/devices/
* directory.
*
* Per-cpu interfaces can be implemented using a struct device_interface.
* See the following for how to do this:
* - drivers/base/intf.c
* - Documentation/driver-model/interface.txt
*/
#ifndef _LINUX_CPU_H_
#define _LINUX_CPU_H_
#include <linux/sysdev.h>
#include <linux/node.h>
#include <linux/compiler.h>
#include <linux/cpumask.h>
#include <asm/semaphore.h>
#include <linux/mutex.h>
struct cpu {
int node_id; /* The node which contains the CPU */
int hotpluggable; /* creates sysfs control file if hotpluggable */
struct sys_device sysdev;
};
extern int register_cpu(struct cpu *cpu, int num);
extern struct sys_device *get_cpu_sysdev(unsigned cpu);
extern int cpu_add_sysdev_attr(struct sysdev_attribute *attr);
extern void cpu_remove_sysdev_attr(struct sysdev_attribute *attr);
extern int cpu_add_sysdev_attr_group(struct attribute_group *attrs);
extern void cpu_remove_sysdev_attr_group(struct attribute_group *attrs);
#ifdef CONFIG_HOTPLUG_CPU
extern void unregister_cpu(struct cpu *cpu);
#endif
struct notifier_block;
#ifdef CONFIG_SMP
/* Need to know about CPUs going up/down? */
#ifdef CONFIG_HOTPLUG_CPU
extern int register_cpu_notifier(struct notifier_block *nb);
extern void unregister_cpu_notifier(struct notifier_block *nb);
#else
#ifndef MODULE
extern int register_cpu_notifier(struct notifier_block *nb);
#else
static inline int register_cpu_notifier(struct notifier_block *nb)
{
return 0;
}
#endif
static inline void unregister_cpu_notifier(struct notifier_block *nb)
{
}
#endif
int cpu_up(unsigned int cpu);
#else
static inline int register_cpu_notifier(struct notifier_block *nb)
{
return 0;
}
static inline void unregister_cpu_notifier(struct notifier_block *nb)
{
}
#endif /* CONFIG_SMP */
extern struct sysdev_class cpu_sysdev_class;
#ifdef CONFIG_HOTPLUG_CPU
/* Stop CPUs going up and down. */
static inline void cpuhotplug_mutex_lock(struct mutex *cpu_hp_mutex)
{
mutex_lock(cpu_hp_mutex);
}
static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
{
mutex_unlock(cpu_hp_mutex);
}
extern void lock_cpu_hotplug(void);
extern void unlock_cpu_hotplug(void);
#define hotcpu_notifier(fn, pri) { \
static struct notifier_block fn##_nb = \
{ .notifier_call = fn, .priority = pri }; \
register_cpu_notifier(&fn##_nb); \
}
#define register_hotcpu_notifier(nb) register_cpu_notifier(nb)
#define unregister_hotcpu_notifier(nb) unregister_cpu_notifier(nb)
int cpu_down(unsigned int cpu);
#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
#else /* CONFIG_HOTPLUG_CPU */
static inline void cpuhotplug_mutex_lock(struct mutex *cpu_hp_mutex)
{ }
static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
{ }
#define lock_cpu_hotplug() do { } while (0)
#define unlock_cpu_hotplug() do { } while (0)
#define lock_cpu_hotplug_interruptible() 0
#define hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
#define register_hotcpu_notifier(nb) do { (void)(nb); } while (0)
#define unregister_hotcpu_notifier(nb) do { (void)(nb); } while (0)
/* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
static inline int cpu_is_offline(int cpu) { return 0; }
#endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_SUSPEND_SMP
extern int disable_nonboot_cpus(void);
extern void enable_nonboot_cpus(void);
#else
static inline int disable_nonboot_cpus(void) { return 0; }
static inline void enable_nonboot_cpus(void) {}
#endif
#endif /* _LINUX_CPU_H_ */