47e627bc8c
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>
137 lines
3.8 KiB
C
137 lines
3.8 KiB
C
/*
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* include/linux/cpu.h - generic cpu definition
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*
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* This is mainly for topological representation. We define the
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* basic 'struct cpu' here, which can be embedded in per-arch
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* definitions of processors.
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*
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* Basic handling of the devices is done in drivers/base/cpu.c
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* and system devices are handled in drivers/base/sys.c.
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*
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* CPUs are exported via sysfs in the class/cpu/devices/
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* directory.
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*
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* Per-cpu interfaces can be implemented using a struct device_interface.
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* See the following for how to do this:
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* - drivers/base/intf.c
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* - Documentation/driver-model/interface.txt
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*/
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#ifndef _LINUX_CPU_H_
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#define _LINUX_CPU_H_
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#include <linux/sysdev.h>
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#include <linux/node.h>
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#include <linux/compiler.h>
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#include <linux/cpumask.h>
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#include <asm/semaphore.h>
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#include <linux/mutex.h>
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struct cpu {
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int node_id; /* The node which contains the CPU */
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int hotpluggable; /* creates sysfs control file if hotpluggable */
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struct sys_device sysdev;
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};
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extern int register_cpu(struct cpu *cpu, int num);
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extern struct sys_device *get_cpu_sysdev(unsigned cpu);
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extern int cpu_add_sysdev_attr(struct sysdev_attribute *attr);
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extern void cpu_remove_sysdev_attr(struct sysdev_attribute *attr);
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extern int cpu_add_sysdev_attr_group(struct attribute_group *attrs);
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extern void cpu_remove_sysdev_attr_group(struct attribute_group *attrs);
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#ifdef CONFIG_HOTPLUG_CPU
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extern void unregister_cpu(struct cpu *cpu);
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#endif
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struct notifier_block;
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#ifdef CONFIG_SMP
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/* Need to know about CPUs going up/down? */
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#ifdef CONFIG_HOTPLUG_CPU
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extern int register_cpu_notifier(struct notifier_block *nb);
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extern void unregister_cpu_notifier(struct notifier_block *nb);
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#else
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#ifndef MODULE
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extern int register_cpu_notifier(struct notifier_block *nb);
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#else
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static inline int register_cpu_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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#endif
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static inline void unregister_cpu_notifier(struct notifier_block *nb)
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{
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}
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#endif
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int cpu_up(unsigned int cpu);
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#else
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static inline int register_cpu_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline void unregister_cpu_notifier(struct notifier_block *nb)
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{
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}
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#endif /* CONFIG_SMP */
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extern struct sysdev_class cpu_sysdev_class;
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#ifdef CONFIG_HOTPLUG_CPU
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/* Stop CPUs going up and down. */
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static inline void cpuhotplug_mutex_lock(struct mutex *cpu_hp_mutex)
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{
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mutex_lock(cpu_hp_mutex);
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}
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static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
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{
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mutex_unlock(cpu_hp_mutex);
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}
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extern void lock_cpu_hotplug(void);
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extern void unlock_cpu_hotplug(void);
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#define hotcpu_notifier(fn, pri) { \
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static struct notifier_block fn##_nb = \
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{ .notifier_call = fn, .priority = pri }; \
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register_cpu_notifier(&fn##_nb); \
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}
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#define register_hotcpu_notifier(nb) register_cpu_notifier(nb)
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#define unregister_hotcpu_notifier(nb) unregister_cpu_notifier(nb)
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int cpu_down(unsigned int cpu);
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#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
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#else /* CONFIG_HOTPLUG_CPU */
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static inline void cpuhotplug_mutex_lock(struct mutex *cpu_hp_mutex)
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{ }
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static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
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{ }
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#define lock_cpu_hotplug() do { } while (0)
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#define unlock_cpu_hotplug() do { } while (0)
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#define lock_cpu_hotplug_interruptible() 0
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#define hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
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#define register_hotcpu_notifier(nb) do { (void)(nb); } while (0)
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#define unregister_hotcpu_notifier(nb) do { (void)(nb); } while (0)
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/* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
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static inline int cpu_is_offline(int cpu) { return 0; }
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#endif /* CONFIG_HOTPLUG_CPU */
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#ifdef CONFIG_SUSPEND_SMP
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extern int disable_nonboot_cpus(void);
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extern void enable_nonboot_cpus(void);
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#else
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static inline int disable_nonboot_cpus(void) { return 0; }
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static inline void enable_nonboot_cpus(void) {}
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#endif
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#endif /* _LINUX_CPU_H_ */
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