Linux内核全局变量总结

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1.current指针

各个平台、各个内核版本中current的实现可能不同；但原理是一样的。该指针一般定义在具体平台的current.h头文件中，类型为struct task_struct：

arch/arm/include/asm/current.h

#define current (get_current())  static inline struct task_struct *get_current(void)

include/linux/sched.h

struct task_struct {    ......    struct thread_info *thread_info;    struct list_head tasks;    pid_t pid;    pid_t tgid;    uid_t uid,euid,suid,fsuid;    gid_t gid,egid,sgid,fsgid;    struct fs_struct *fs;  //本节将大量使用这个    struct files_struct *files;    ......  }

2.jiffies系统开机后“滴答”数

include/linux/jiffies.h

extern u64 __jiffy_data jiffies_64;extern unsigned long volatile __jiffy_data jiffies;

3.HZ、tick系统晶振主频，平台相关

arch/arm/include/asm/param.h

#ifdef __KERNEL__# define HZ             CONFIG_HZ       /* Internal kernel timer frequency */# define USER_HZ        100             /* User interfaces are in "ticks" */# define CLOCKS_PER_SEC (USER_HZ)       /* like times() */#else# define HZ             100#endif

include/linux/timex.h

extern unsigned long tick_usec;         /* USER_HZ period (usec) */extern unsigned long tick_nsec;         /* ACTHZ          period (nsec) */

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