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![Linus Torvalds](/assets/img/avatar_default.png)
SLAB uses get/put_online_cpus() which use a mutex which is itself only initialized when cpu_hotplug_init() is called. Currently we hang suring boot in SLAB due to doing that too late. Reported by James Bottomley and Sachin Sant (and possibly others). Debugged by Benjamin Herrenschmidt. This just removes the dynamic initialization of the data structures, and replaces it with a static one, avoiding this dependency entirely, and removing one unnecessary special initcall. Tested-by: Sachin Sant <sachinp@in.ibm.com> Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
133 lines
3.6 KiB
C
133 lines
3.6 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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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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extern int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls);
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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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void notify_cpu_starting(unsigned int cpu);
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extern void cpu_maps_update_begin(void);
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extern void cpu_maps_update_done(void);
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#else /* CONFIG_SMP */
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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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static inline void cpu_maps_update_begin(void)
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{
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}
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static inline void cpu_maps_update_done(void)
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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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extern void get_online_cpus(void);
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extern void put_online_cpus(void);
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#define hotcpu_notifier(fn, pri) { \
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static struct notifier_block fn##_nb __cpuinitdata = \
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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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#else /* CONFIG_HOTPLUG_CPU */
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#define get_online_cpus() do { } while (0)
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#define put_online_cpus() do { } while (0)
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#define hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
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/* These aren't inline functions due to a GCC bug. */
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#define register_hotcpu_notifier(nb) ({ (void)(nb); 0; })
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#define unregister_hotcpu_notifier(nb) ({ (void)(nb); })
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#endif /* CONFIG_HOTPLUG_CPU */
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#ifdef CONFIG_PM_SLEEP_SMP
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extern int suspend_cpu_hotplug;
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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 /* !CONFIG_PM_SLEEP_SMP */
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#define suspend_cpu_hotplug 0
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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 /* !CONFIG_PM_SLEEP_SMP */
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#endif /* _LINUX_CPU_H_ */
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