//任务机构体，大小大概1024字节
struct task_struct {/* these are hardcoded - don't touch */ //硬件代码 不可被修改volatile long state;	//状态标志 /* -1 unrunnable, 0 runnable, >0 stopped */ long counter;           //计数long priority;          //优先权unsigned long signal;   //信号unsigned long blocked;	//信号标志的bit映射 /* bitmap of masked signals */            unsigned long flags;	//上个进程标志/* per process flags, defined below */    int errno;              //出错代码int debugreg[8];        //硬件编译寄存器。/* Hardware debugging registers */  /* various fields */ //可变区域struct task_struct *next_task, *prev_task;            //本结构的链表双向指针struct sigaction sigaction1[32];                      //信号活动数组unsigned long saved_kernel_stack;   //内核中保存的堆栈点           unsigned long kernel_stack_page;    //内核堆栈页int exit_code, exit_signal;         //结束代码，结束信号int elf_executable:1;      //是否自己可以执行标志int dumpable:1;            //是否可以拆卸标志int swappable:1;           //是否可以交换标志int did_exec:1;            //是否为执行文件标志//启动代码点，结束代码点，结束数据点，断点开始点，断点，堆栈开始点，虚拟映射页开始点！unsigned long start_code,end_code,end_data,start_brk,brk,start_stack,start_mmap;//变量开始点，变量结束点，环境开始点，环境结束点unsigned long arg_start, arg_end, env_start, env_end;//进程id,组，会话，引入点int pid,pgrp,session,leader;//分组数组int	groups[NGROUPS];/* * pointers to (original) parent process, youngest child, younger sibling,* older sibling, respectively.  (p->father can be replaced with * p->p_pptr->pid)*///指向最原始的进程任务指针，父进程任务指针，子进程任务指针，新兄弟进程任务指针，旧兄弟进程任务指针。struct task_struct *p_opptr,*p_pptr, *p_cptr, *p_ysptr, *p_osptr;//任务队列指针struct wait_queue *wait_chldexit;	/* for wait4() *//** For ease of programming... Normal sleeps don't need to* keep track of a wait-queue: every task has an entry of its own*///real user ID (uid): 实际用户ID,指的是进程执行者是谁//effective user ID (euid): 有效用户ID,指进程执行时对文件的访问权限//saved set-user-ID (saved uid): 保存设置用户ID。是进程刚开始执行时，euid的副本。在执行exec调用之后能重新恢复原来的effectiv user ID.unsigned short uid,euid,suid; //用户ID，有效用户ID，保存设置用户IDunsigned short gid,egid,sgid; //组ID，有效组ID，保存设置组ID；unsigned long timeout;        //超时时间unsigned long it_real_value, it_prof_value, it_virt_value; //真实间隔定时器计数器的当前值，PROF间隔定时器计数器的当前值，虚拟间隔定时器计数器的当前值unsigned long it_real_incr, it_prof_incr, it_virt_incr;    //真实间隔定时器计数器的初始值，PROF间隔定时器计数器的初始值，虚拟间隔定时器计数器的初始值long utime,stime,cutime,cstime,start_time;    //用户时间，系统时间,累计用户时间，进程启动时间unsigned long min_flt, maj_flt;               //次要页错误的数量,主要页错误的数量unsigned long cmin_flt, cmaj_flt;             //累计次要页错误，累计主要页错误struct rlimit rlim[RLIM_NLIMITS];             //右限制值数组unsigned short used_math;                     //被使用的数字unsigned short rss;	/* number of resident pages */        //寄存页号char comm[16];                                //comm口struct vm86_struct * vm86_info;               //86虚拟机结构unsigned long screen_bitmap;                  //屏幕位映射
/* file system info */ //文件系统信息int link_count;    //链接数int tty;		   //终端类型 /* -1 if no tty, so it must be signed */unsigned short umask;          //权限掩码struct inode * pwd;            //密码节点指针struct inode * root;           //root节点指针struct inode * executable;     //执行表节点指针struct vm_area_struct * mmap;  //虚拟区域映射指针struct shm_desc *shm;          //struct sem_undo *semun;        //信号量操作标志struct file * filp[NR_OPEN];   //已经打开的文件描述字数组fd_set close_on_exec;          //进程所有文件描述符（文件句柄）的位图标
/* ldt for this task - used by Wine.  If NULL, default_ldt is used */struct desc_struct *ldt;       //局部描述符表
/* tss for this task */struct tss_struct tss;         //任务状态段信息结构
#ifdef NEW_SWAPunsigned long old_maj_flt;	/* old value of maj_flt */unsigned long dec_flt;		/* page fault count of the last time */unsigned long swap_cnt;		/* number of pages to swap on next pass */short swap_table;		/* current page table */short swap_page;		/* current page */
#endif NEW_SWAPstruct vm_area_struct *stk_vma; //虚拟区域映射指针
};