fork1.1 tast_struct 结构体和thread_info结构体

struct task_struct {//进程状态（-1就绪态，0运行态，>0停止态）volatile long state;/* -1 unrunnable, 0 runnable, >0 stopped *///进程内核栈void *stack;//有几个进程只在使用此结构atomic_t usage;//标记unsigned int flags;/* per process flags, defined below *///ptrace系统调用，关于实现断点调试，跟踪进程运行。unsigned int ptrace;//锁的深度int lock_depth;/* BKL lock depth *///SMP实现无加锁的进程切换#ifdef CONFIG_SMP#ifdef __ARCH_WANT_UNLOCKED_CTXSWint oncpu;#endif#endif//关于进程调度int prio, static_prio, normal_prio;//优先级unsigned int rt_priority;//关于进程const struct sched_class *sched_class;struct sched_entity se;struct sched_rt_entity rt;//preempt_notifier结构体链表#ifdef CONFIG_PREEMPT_NOTIFIERS/* list of struct preempt_notifier: */struct hlist_head preempt_notifiers;#endif/* * fpu_counter contains the number of consecutive context switches * that the FPU is used. If this is over a threshold, the lazy fpu * saving becomes unlazy to save the trap. This is an unsigned char * so that after 256 times the counter wraps and the behavior turns * lazy again; this to deal with bursty apps that only use FPU for * a short time */  //FPU使用计数unsigned char fpu_counter;//块设备I/O层的跟踪工具#ifdef CONFIG_BLK_DEV_IO_TRACEunsigned int btrace_seq;#endif//进程调度策略相关的字段unsigned int policy;cpumask_t cpus_allowed;//RCU同步原语#ifdef CONFIG_TREE_PREEMPT_RCUint rcu_read_lock_nesting;char rcu_read_unlock_special;struct rcu_node *rcu_blocked_node;struct list_head rcu_node_entry;#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU *///用于调度器统计进程运行信息#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)struct sched_info sched_info;#endif//用于构架进程链表struct list_head tasks;struct plist_node pushable_tasks;//关于进程的地址空间，指向进程的地址空间。（链表和红黑树）struct mm_struct *mm, *active_mm;/* task state *///进程状态参数int exit_state;//退出信号处理int exit_code, exit_signal;//接收父进程终止的时候会发送信号int pdeath_signal;  /*  The signal sent when the parent dies  *//* ??? */unsigned int personality;unsigned did_exec:1;unsigned in_execve:1;/* Tell the LSMs that the process is doing an * execve */unsigned in_iowait:1;/* Revert to default priority/policy when forking */unsigned sched_reset_on_fork:1;//进程pid，父进程ppid。pid_t pid;pid_t tgid;//防止内核堆栈溢出#ifdef CONFIG_CC_STACKPROTECTOR/* Canary value for the -fstack-protector gcc feature */unsigned long stack_canary;#endif/* * pointers to (original) parent process, youngest child, younger sibling, * older sibling, respectively.  (p->father can be replaced with * p->real_parent->pid) */  //这部分是用来进行维护进程之间的亲属关系的。 //初始化父进程struct task_struct *real_parent; /* real parent process *///接纳终止的进程struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports *//* * children/sibling forms the list of my natural children */ //维护子进程链表struct list_head children;/* list of my children *///兄弟进程链表struct list_head sibling;/* linkage in my parent's children list *///线程组组长struct task_struct *group_leader;/* threadgroup leader *//* * ptraced is the list of tasks this task is using ptrace on. * This includes both natural children and PTRACE_ATTACH targets. * p->ptrace_entry is p's link on the p->parent->ptraced list. */  //ptrace，系统调用，关于断点调试。struct list_head ptraced;struct list_head ptrace_entry;//PID与PID散列表的联系/* PID/PID hash table linkage. */struct pid_link pids[PIDTYPE_MAX];//维护一个链表，里面有该进程所有的线程struct list_head thread_group;//do_fork()函数struct completion *vfork_done;/* for vfork() */int __user *set_child_tid;/* CLONE_CHILD_SETTID */int __user *clear_child_tid;/* CLONE_CHILD_CLEARTID *///描述CPU时间的内容//utime是用户态下的执行时间//stime是内核态下的执行时间cputime_t utime, stime, utimescaled, stimescaled;cputime_t gtime;cputime_t prev_utime, prev_stime;//上下文切换计数unsigned long nvcsw, nivcsw; /* context switch counts */struct timespec start_time; /* monotonic time */struct timespec real_start_time;/* boot based time *//* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific *///缺页统计unsigned long min_flt, maj_flt;struct task_cputime cputime_expires;struct list_head cpu_timers[3];/* process credentials *///进程身份凭据const struct cred *real_cred;/* objective and real subjective task * credentials (COW) */const struct cred *cred;/* effective (overridable) subjective task * credentials (COW) */struct mutex cred_guard_mutex;/* guard against foreign influences on * credential calculations * (notably. ptrace) */struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT *///去除路径以后的可执行文件名称，进程名char comm[TASK_COMM_LEN]; /* executable name excluding path     - access with [gs]et_task_comm (which lock       it with task_lock())     - initialized normally by setup_new_exec *//* file system info *///文件系统信息int link_count, total_link_count;#ifdef CONFIG_SYSVIPC/* ipc stuff *///进程通信struct sysv_sem sysvsem;#endif#ifdef CONFIG_DETECT_HUNG_TASK/* hung task detection */unsigned long last_switch_count;#endif//该进程在特点CPU下的状态/* CPU-specific state of this task */struct thread_struct thread;//文件系统信息结构体/* filesystem information */struct fs_struct *fs;//打开文件相关信息结构体/* open file information */struct files_struct *files;/* namespaces *///命名空间：struct nsproxy *nsproxy;/* signal handlers *///关于进行信号处理struct signal_struct *signal;struct sighand_struct *sighand;sigset_t blocked, real_blocked;sigset_t saved_sigmask;/* restored if set_restore_sigmask() was used */struct sigpending pending;unsigned long sas_ss_sp;size_t sas_ss_size;int (*notifier)(void *priv);void *notifier_data;sigset_t *notifier_mask;//进程审计struct audit_context *audit_context;#ifdef CONFIG_AUDITSYSCALLuid_t loginuid;unsigned int sessionid;#endifseccomp_t seccomp;#ifdef CONFIG_UTRACEstruct utrace *utrace;unsigned long utrace_flags;#endif//线程跟踪组/* Thread group tracking */   u32 parent_exec_id;   u32 self_exec_id;/* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed, * mempolicy */spinlock_t alloc_lock;//中断#ifdef CONFIG_GENERIC_HARDIRQS/* IRQ handler threads */struct irqaction *irqaction;#endif//task_rq_lock函数所使用的锁/* Protection of the PI data structures: */spinlock_t pi_lock;//基于PI协议的等待互斥锁#ifdef CONFIG_RT_MUTEXES/* PI waiters blocked on a rt_mutex held by this task */struct plist_head pi_waiters;/* Deadlock detection and priority inheritance handling */struct rt_mutex_waiter *pi_blocked_on;#endif//死锁检测#ifdef CONFIG_DEBUG_MUTEXES/* mutex deadlock detection */struct mutex_waiter *blocked_on;#endif//中断#ifdef CONFIG_TRACE_IRQFLAGSunsigned int irq_events;int hardirqs_enabled;unsigned long hardirq_enable_ip;unsigned int hardirq_enable_event;unsigned long hardirq_disable_ip;unsigned int hardirq_disable_event;int softirqs_enabled;unsigned long softirq_disable_ip;unsigned int softirq_disable_event;unsigned long softirq_enable_ip;unsigned int softirq_enable_event;int hardirq_context;int softirq_context;#endif//lockdep#ifdef CONFIG_LOCKDEP# define MAX_LOCK_DEPTH 48ULu64 curr_chain_key;int lockdep_depth;unsigned int lockdep_recursion;struct held_lock held_locks[MAX_LOCK_DEPTH];gfp_t lockdep_reclaim_gfp;#endif//日志文件/* journalling filesystem info */void *journal_info;/* stacked block device info *///块设备链表struct bio *bio_list, **bio_tail;/* VM state *///虚拟内存状态，内存回收struct reclaim_state *reclaim_state;//存放块设备I/O流量信息struct backing_dev_info *backing_dev_info;//I/O调度器所用信息struct io_context *io_context;unsigned long ptrace_message;siginfo_t *last_siginfo; /* For ptrace use.  *///记录进程I/O计数struct task_io_accounting ioac;#if defined(CONFIG_TASK_XACCT)u64 acct_rss_mem1;/* accumulated rss usage */u64 acct_vm_mem1;/* accumulated virtual memory usage */cputime_t acct_timexpd;/* stime + utime since last update */#endif//CPUSET功能#ifdef CONFIG_CPUSETSnodemask_t mems_allowed;/* Protected by alloc_lock */#ifndef __GENKSYMS__/* * This does not change the size of the struct_task(2+2+4=4+4) * so the offsets of the remaining fields are unchanged and  * therefore the kABI is preserved.  Only the kernel uses * cpuset_mem_spread_rotor and cpuset_slab_spread_rotor so * it is safe to change it to use shorts instead of ints. */   unsigned short cpuset_mem_spread_rotor;unsigned short cpuset_slab_spread_rotor;int mems_allowed_change_disable;#elseint cpuset_mem_spread_rotor;int cpuset_slab_spread_rotor;#endif#endif//Control Groups#ifdef CONFIG_CGROUPS/* Control Group info protected by css_set_lock */struct css_set *cgroups;/* cg_list protected by css_set_lock and tsk->alloc_lock */struct list_head cg_list;#endif//futex同步机制#ifdef CONFIG_FUTEXstruct robust_list_head __user *robust_list;#ifdef CONFIG_COMPATstruct compat_robust_list_head __user *compat_robust_list;#endifstruct list_head pi_state_list;struct futex_pi_state *pi_state_cache;#endif//关于内存检测工具Performance Event#ifdef CONFIG_PERF_EVENTS#ifndef __GENKSYMS__void * __reserved_perf__;#elsestruct perf_event_context *perf_event_ctxp;#endifstruct mutex perf_event_mutex;struct list_head perf_event_list;#endif//非一致内存访问#ifdef CONFIG_NUMAstruct mempolicy *mempolicy;/* Protected by alloc_lock */short il_next;#endif//文件系统互斥资源atomic_t fs_excl;/* holding fs exclusive resources *///RCU链表struct rcu_head rcu;/* * cache last used pipe for splice */  //管道struct pipe_inode_info *splice_pipe;//延迟计数#ifdefCONFIG_TASK_DELAY_ACCTstruct task_delay_info *delays;#endif#ifdef CONFIG_FAULT_INJECTIONint make_it_fail;#endifstruct prop_local_single dirties;#ifdef CONFIG_LATENCYTOPint latency_record_count;struct latency_record latency_record[LT_SAVECOUNT];#endif/* * time slack values; these are used to round up poll() and * select() etc timeout values. These are in nanoseconds. */  //time slack values,常用于poll和select函数unsigned long timer_slack_ns;unsigned long default_timer_slack_ns;//socket控制消息struct list_head*scm_work_list;#ifdef CONFIG_FUNCTION_GRAPH_TRACER//ftrace跟踪器/* Index of current stored adress in ret_stack */int curr_ret_stack;/* Stack of return addresses for return function tracing */struct ftrace_ret_stack*ret_stack;/* time stamp for last schedule */unsigned long long ftrace_timestamp;/* * Number of functions that haven't been traced * because of depth overrun. */atomic_t trace_overrun;/* Pause for the tracing */atomic_t tracing_graph_pause;#endif#ifdef CONFIG_TRACING/* state flags for use by tracers */unsigned long trace;/* bitmask of trace recursion */unsigned long trace_recursion;#endif /* CONFIG_TRACING *//* reserved for Red Hat */unsigned long rh_reserved[2];#ifndef __GENKSYMS__struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];#ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */struct memcg_batch_info {int do_batch;/* incremented when batch uncharge started */struct mem_cgroup *memcg; /* target memcg of uncharge */unsigned long bytes; /* uncharged usage */unsigned long memsw_bytes; /* uncharged mem+swap usage */} memcg_batch;#endif#endif};