本文详细介绍了Linux内核中的关键数据结构task_struct，涵盖了进程状态、优先级、信号处理、调度策略、地址空间、资源保护、信号处理等多个方面，全面解析了进程控制块的各个成员及其功能。
我们知道，进程是程序的动态运行实例。且CPU会对这些进程进行调度，使得程序得以执行。那么如果有多个进程同时要求执行，CPU如何判断该执行哪一个，执行多长时间等等问题呢。学习过操作系统的话，应该能知道对于每一个进程，都有一个进程控制块（PCB），维护对应进程的一些信息。在Linux内核，这个PCB就是一个名为task_struct的结构体。本篇博客，主要就是介绍构成task_struct结构体的成员。
1.进程状态
volatile long state;
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表示进程运行时的状态，-1表示不可运行，0表示可运行，>0表示已经停止。
state的可能取值如下：
TASK_RUNNING：表示进程要么正在执行，要么正要准备执行（已经就绪），正在等待cpu时间片的调度。
TASK_INTERRUPTIBLE：表示进程因为等待一些条件而被挂起（阻塞）而所处的状态。这些条件主要包括：硬中断、资源、一些信号……，一旦等待的条件成立，进程就会从该状态（阻塞）迅速转化成为就绪状态TASK_RUNNING（执行或准备执行态）。
TASK_UNINTERRUPTIBLE：意义与上一个类似对于处于此状态的进程，即使传递一个信号或者有一个外部中断都不能唤醒他们。只有它所等待的资源可用的时候，它才会被唤醒。这个标志很少用，但是并不代表没有任何用处，其实他的作用非常大，特别是对于驱动刺探相关的硬件过程很重要，这个刺探过程不能被一些其他的东西给中断，否则就会让进程进入不可预测的状态。
TASK_STOPPED：表示进程被停止执行，当进程接收到SIGSTOP、SIGTTIN、SIGTSTP或者SIGTTOU信号之后就会进入该状态。
TASK_TRACED：表示进程被debugger等进程监视，进程执行被调试程序所停止，当一个进程被另外的进程所监视，每一个信号都会让进程进入该状态。
2.进程标志
unsigned long flags;
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进程当前的标志状态，但不是运行状态，用于内核识别进程当前的状态，以备下一步操作。
flags可能取值如下：
PF_FORKNOEXEC 进程刚创建，但还没执行。
PF_SUPERPRIV 超级用户特权。
PF_DUMPCORE dumped core。
PF_SIGNALED 进程被信号(signal)杀出。
PF_EXITING 进程开始关闭。
3.进程优先级
int prio, static_prio, normal_prio;
unsigned int rt_priority;
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表示此进程的运行优先级
prio:表示动态优先级，根据static_prio和交互性奖罚算出。
static_prio:进程的静态优先级，在进程创建时确定，范围从-20到19，越小优先级越高。
normal_prio的优先级取决于静态优先级和调度策略。rt_priority用于保存实时优先级，范围是0到MAX_RT_PRIO-1（即99）。
4.进程标识符
pid_t pid;
pid_t tgid;
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pid进程标识符，相当于每一个学生的学号一样，标识符唯一标识进程。
tpid是线程组号。
5.进程内核栈
void *stack;
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进程内核栈。Linux内核通过thread_union联合体来表示进程的内核栈，其中THREAD_SIZE宏的大小为8192。 通过alloc_thread_info函数分配它的内核栈，通过free_thread_info函数释放所分配的内核栈。
union thread_union {
struct thread_info thread_info;
unsigned long stack[THREAD_SIZE/sizeof(long)];
};
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6.进程的亲属关系
struct task_struct *real_parent; /* real parent process */
struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports */
/*
* children/sibling forms the list of my natural children
*/
struct list_head children; /* list of my children */
struct list_head sibling; /* linkage in my parent's children list */
struct task_struct *group_leader; /* threadgroup leader */
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real_parent——是进程的“亲生父亲”。如果创建进程的父进程不再存在，则指向PID为1的init进程
parent——是进程的父进程。进程终止时，必须向它的父进程发送信号。它的值通常与real_parent相同。
children——表示链表的头部，链表中的所有元素都是它的子进程。
sibling——用于把当前进程插入到兄弟链表中。
group_leader——指向其所在进程组的领头进程
7.ptrace系统调用
unsigned int ptrace;
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ptrace 提供了一种父进程可以控制子进程运行，并可以检查和改变它的核心image。
它主要用于实现断点调试。一个被跟踪的进程运行中，直到发生一个信号,则进程被中止，并且通知其父进程。在进程中止的状态下，进程的内存空间可以被读写。父进程还可以使子进程继续执行，并选择是否是否忽略引起中止的信号。成员ptrace被设置为0时表示不需要被跟踪。
8.调度策略相关
const struct sched_class *sched_class;
struct sched_entity se;
struct sched_rt_entity rt;
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sched_class:调度类
se:普通进程的调用实体，每个进程都有其中之一的实体
rt:实时进程的调用实体，每个进程都有其中之一的实体
9.进程地址空间
struct mm_struct *mm, *active_mm;
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mm:进程所拥有的用户空间内存描述符，内核线程无的mm为NULL
active_mm:指向进程运行时所使用的内存描述符， 对于普通进程而言，这两个指针变量的值相同。但是内核线程kernel thread是没有进程地址空间的，所以内核线程的tsk->mm域是空（NULL）。但是内核必须知道用户空间包含了什么，因此它的active_mm成员被初始化为前一个运行进程的active_mm值。
10.判断标志
int exit_code, exit_signal;
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;
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exit_code:用于设置进程的终止代号，这个值要么是_exit()或exit_group()系统调用参数（正常终止），要么是由内核提供的一个错误代号（异常终止）。
exit_signal:被置为-1时表示是某个线程组中的一员。只有当线程组的最后一个成员终止时，才会产生一个信号，以通知线程组的领头进程的父进程。
personality：用于处理不同的ABI，参见Linux-Man。
did_exec：用于记录进程代码是否被execve()函数所执行。
in_execve：用于通知LSM是否被do_execve()函数所调用。
in_iowait：用于判断是否进行iowait计数。
11.时间
cputime_t utime, stime, utimescaled, stimescaled;
cputime_t gtime;
cputime_t prev_utime, prev_stime;
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 */
unsigned long min_flt, maj_flt;
struct task_cputime cputime_expires;
struct list_head cpu_timers[3];
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utime/stime：用于记录进程在用户态/内核态下所经过的节拍数（定时器）。
utimescaled/stimescaled：用于记录进程在用户态/内核态的运行时间，但它们以处理器的频率为刻度。
gtime：以节拍计数的虚拟机运行时间（guest time）。
prev_utime/prev_stime：是先前的运行时间，请参考补丁说明http://lkml.indiana.edu/hypermail/linux/kernel/1003.3/02431.html。
nvcsw/nivcsw：自愿（voluntary）/非自愿（involuntary）上下文切换计数。
start_time、real_start_time：都是进程创建时间，real_start_time还包含了进程睡眠时间，常用于/proc/pid/stat，补丁说明请参考http://lkml.indiana.edu/hypermail/linux/kernel/0705.0/2094.html
cputime_expires：用来统计进程或进程组被跟踪的处理器时间，其中的三个成员对应着cpu_timers[3]的三个链表。
min_flt,maj_flt：缺页统计。
12.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;
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signal：指向进程的信号描述符。
sighand：指向进程的信号处理程序描述符。
blocked：表示被阻塞信号的掩码，real_blocked表示临时掩码。
pending：存放私有挂起信号的数据结构。
sas_ss_sp：是信号处理程序备用堆栈的地址，sas_ss_size表示堆栈的大小。
notifier_data/notifier_mask：设备驱动程序常用notifier指向的函数来阻塞进程的某些信号（notifier_mask是这些信号的位掩码），notifier_data指的是notifier所指向的函数可能使用的数据。
13.其他
（1）用于保护资源分配或释放的自旋锁
/* Protection of (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed,
* mempolicy */
spinlock_t alloc_lock;
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（2）进程描述符使用计数，被置为2时，表示进程描述符正在被使用而且其相应的进程处于活动状态。
atomic_t usage;
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（3）用于表示获取大内核锁的次数，如果进程未获得过锁，则置为-1。
int lock_depth; /* BKL lock depth */
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（4）在SMP上帮助实现无加锁的进程切换（unlocked context switches）
#ifdef CONFIG_SMP
#ifdef __ARCH_WANT_UNLOCKED_CTXSW
int oncpu;
#endif
#endif
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（5）preempt_notifier结构体链表
#ifdef CONFIG_PREEMPT_NOTIFIERS
/* list of struct preempt_notifier: */
struct hlist_head preempt_notifiers;
#endif
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（6）FPU使用计数
unsigned char fpu_counter;
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（7）、blktrace是一个针对Linux内核中块设备I/O层的跟踪工具。
#ifdef CONFIG_BLK_DEV_IO_TRACE
unsigned int btrace_seq;
#endif
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（8）RCU同步原语
#ifdef CONFIG_PREEMPT_RCU
int rcu_read_lock_nesting;
char rcu_read_unlock_special;
struct list_head rcu_node_entry;
#endif /* #ifdef CONFIG_PREEMPT_RCU */
#ifdef CONFIG_TREE_PREEMPT_RCU
struct rcu_node *rcu_blocked_node;
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
#ifdef CONFIG_RCU_BOOST
struct rt_mutex *rcu_boost_mutex;
#endif /* #ifdef CONFIG_RCU_BOOST */
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（9）用于调度器统计进程的运行信息
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
struct sched_info sched_info;
#endif
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（10）、用于构建进程链表
struct list_head tasks;
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（11）、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
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（12）PID散列表和链表
/* PID/PID hash table linkage. */
struct pid_link pids[PIDTYPE_MAX];
struct list_head thread_group; //线程组中所有进程的链表
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（13）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 */
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在执行do_fork()时，如果给定特别标志，则vfork_done会指向一个特殊地址。
如果copy_process函数的clone_flags参数的值被置为CLONE_CHILD_SETTID或CLONE_CHILD_CLEARTID，则会把child_tidptr参数的值分别复制到set_child_tid和clear_child_tid成员。这些标志说明必须改变子进程用户态地址空间的child_tidptr所指向的变量的值。
（14）进程权能
const struct cred __rcu *real_cred; /* objective and real subjective task
* credentials (COW) */
const struct cred __rcu *cred; /* effective (overridable) subjective task
* credentials (COW) */
struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT */
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（15）相应的程序名
char comm[TASK_COMM_LEN]
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（16）文件
/* file system info */
int link_count, total_link_count;
/* filesystem information */
struct fs_struct *fs;
/* open file information */
struct files_struct *files;
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fs：用来表示进程与文件系统的联系，包括当前目录和根目录。\
files：表示进程当前打开的文件。
（17）进程通信（SYSVIPC）
#ifdef CONFIG_SYSVIPC
/* ipc stuff */
struct sysv_sem sysvsem;
#endif
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（18）处理器特有数据
struct thread_struct thread;
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（19）命名空间
struct nsproxy *nsproxy;
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（20）进程审计
struct audit_context *audit_context;
#ifdef CONFIG_AUDITSYSCALL
uid_t loginuid;
unsigned int sessionid;
#endif
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（21）secure computing
seccomp_t seccomp;
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（22）用于copy_process函数使用CLONE_PARENT 标记时
/* Thread group tracking */
u32 parent_exec_id;
u32 self_exec_id;
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（23）中断
#ifdef CONFIG_GENERIC_HARDIRQS
/* IRQ handler threads */
struct irqaction *irqaction;
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
unsigned int irq_events;
unsigned long hardirq_enable_ip;
unsigned long hardirq_disable_ip;
unsigned int hardirq_enable_event;
unsigned int hardirq_disable_event;
int hardirqs_enabled;
int hardirq_context;
unsigned long softirq_disable_ip;
unsigned long softirq_enable_ip;
unsigned int softirq_disable_event;
unsigned int softirq_enable_event;
int softirqs_enabled;
int softirq_context;
#endif
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（24）task_rq_lock函数所使用的锁
/* Protection of the PI data structures: */
raw_spinlock_t pi_lock;
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（25）基于PI协议的等待互斥锁，其中PI指的是priority inheritance（优先级继承）
#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
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（26）死锁检测
#ifdef CONFIG_DEBUG_MUTEXES
/* mutex deadlock detection */
struct mutex_waiter *blocked_on;
#endif
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（27）lockdep，参见内核说明文档linux-2.6.38.8/Documentation/lockdep-design.txt
#ifdef CONFIG_LOCKDEP
# define MAX_LOCK_DEPTH 48UL
u64 curr_chain_key;
int lockdep_depth;
unsigned int lockdep_recursion;
struct held_lock held_locks[MAX_LOCK_DEPTH];
gfp_t lockdep_reclaim_gfp;
#endif
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（28）JFS文件系统
/* journalling filesystem info */
void *journal_info;
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（29）块设备链表
/* stacked block device info */
struct bio_list *bio_list;
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（30）内存回收
struct reclaim_state *reclaim_state;
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（31）存放块设备I/O数据流量信息
struct backing_dev_info *backing_dev_info;
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（32）I/O调度器所使用的信息
struct io_context *io_context;
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（33）CPUSET功能
#ifdef CONFIG_CPUSETS
nodemask_t mems_allowed; /* Protected by alloc_lock */
int mems_allowed_change_disable;
int cpuset_mem_spread_rotor;
int cpuset_slab_spread_rotor;
#endif
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（34）Control Groups
#ifdef CONFIG_CGROUPS
/* Control Group info protected by css_set_lock */
struct css_set __rcu *cgroups;
/* cg_list protected by css_set_lock and tsk->alloc_lock */
struct list_head cg_list;
#endif
#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
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（35）futex同步机制
#ifdef CONFIG_FUTEX
struct robust_list_head __user *robust_list;
#ifdef CONFIG_COMPAT
struct compat_robust_list_head __user *compat_robust_list;
#endif
struct list_head pi_state_list;
struct futex_pi_state *pi_state_cache;
#endif
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（36）非一致内存访问（NUMA Non-Uniform Memory Access）
#ifdef CONFIG_NUMA
struct mempolicy *mempolicy; /* Protected by alloc_lock */
short il_next;
#endif
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（37）文件系统互斥资源
atomic_t fs_excl; /* holding fs exclusive resources */
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（38）RCU链表
struct rcu_head rcu;
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（39）管道
struct pipe_inode_info *splice_pipe;
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（40）延迟计数
1. #ifdef CONFIG_TASK_DELAY_ACCT
2. struct task_delay_info *delays;
3. #endif
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（41）fault injection，参考内核说明文件linux-2.6.38.8/Documentation/fault-injection/fault-injection.txt
#ifdef CONFIG_FAULT_INJECTION
int make_it_fail;
#endif
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以下是摘自Linux内核2.6.32版的task_struct源码。
struct task_struct {
volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */
void *stack;
atomic_t usage;
unsigned int flags; /* per process flags, defined below */
unsigned int ptrace;
int lock_depth; /* BKL lock depth */
#ifdef CONFIG_SMP
#ifdef __ARCH_WANT_UNLOCKED_CTXSW
int oncpu;
#endif
#endif
int prio, static_prio, normal_prio;
unsigned int rt_priority;
const struct sched_class *sched_class;
struct sched_entity se;
struct sched_rt_entity rt;
#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
*/
unsigned char fpu_counter;
#ifdef CONFIG_BLK_DEV_IO_TRACE
unsigned int btrace_seq;
#endif
unsigned int policy;
cpumask_t cpus_allowed;
#ifdef CONFIG_TREE_PREEMPT_RCU
int 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 */
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
struct sched_info sched_info;
#endif
struct list_head tasks;
struct plist_node pushable_tasks;
struct mm_struct *mm, *active_mm;
/* task state */
int exit_state;
int exit_code, exit_signal;
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;
pid_t pid;
pid_t tgid;
#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)
*/
struct task_struct *real_parent; /* real parent process */
struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports */
/*
* children/sibling forms the list of my natural children
*/
struct list_head children; /* list of my children */
struct list_head sibling; /* linkage in my parent's children list */
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.
*/
struct list_head ptraced;
struct list_head ptrace_entry;
/*
* This is the tracer handle for the ptrace BTS extension.
* This field actually belongs to the ptracer task.
*/
struct bts_context *bts;
/* PID/PID hash table linkage. */
struct pid_link pids[PIDTYPE_MAX];
struct list_head thread_group;
struct completion *vfork_done; /* for vfork() */
int __user *set_child_tid; /* CLONE_CHILD_SETTID */
int __user *clear_child_tid; /* CLONE_CHILD_CLEARTID */
cputime_t utime, stime, utimescaled, stimescaled;
cputime_t gtime;
cputime_t prev_utime, prev_stime;
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 */
unsigned long min_flt, maj_flt;
struct task_cputime cputime_expires;
struct list_head cpu_timers[3];
/* process credentials */
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 */
char comm[TASK_COMM_LEN]; /* executable name excluding path
- access with [gs]et_task_comm (which lock
it with task_lock())
- initialized normally by flush_old_exec */
/* file system info */
int link_count, total_link_count;
#ifdef CONFIG_SYSVIPC
/* ipc stuff */
struct sysv_sem sysvsem;
#endif
#ifdef CONFIG_DETECT_HUNG_TASK
/* hung task detection */
unsigned long last_switch_count;
#endif
/* CPU-specific state of this task */
struct thread_struct thread;
/* filesystem information */
struct fs_struct *fs;
/* open file information */
struct files_struct *files;
/* namespaces */
struct nsproxy *nsproxy;
/* signal handlers */
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;
struct audit_context *audit_context;
#ifdef CONFIG_AUDITSYSCALL
uid_t loginuid;
unsigned int sessionid;
#endif
seccomp_t seccomp;
/* 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;
#ifdef CONFIG_GENERIC_HARDIRQS
/* IRQ handler threads */
struct irqaction *irqaction;
#endif
/* Protection of the PI data structures: */
spinlock_t pi_lock;
#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
#ifdef CONFIG_DEBUG_MUTEXES
/* mutex deadlock detection */
struct mutex_waiter *blocked_on;
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
unsigned 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
#ifdef CONFIG_LOCKDEP
# define MAX_LOCK_DEPTH 48UL
u64 curr_chain_key;
int lockdep_depth;
unsigned int lockdep_recursion;
struct held_lock held_locks[MAX_LOCK_DEPTH];
gfp_t lockdep_reclaim_gfp;
#endif
/* journalling filesystem info */
void *journal_info;
/* stacked block device info */
struct bio *bio_list, **bio_tail;
/* VM state */
struct reclaim_state *reclaim_state;
struct backing_dev_info *backing_dev_info;
struct io_context *io_context;
unsigned long ptrace_message;
siginfo_t *last_siginfo; /* For ptrace use. */
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
#ifdef CONFIG_CPUSETS
nodemask_t mems_allowed; /* Protected by alloc_lock */
int cpuset_mem_spread_rotor;
#endif
#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
#ifdef CONFIG_FUTEX
struct robust_list_head __user *robust_list;
#ifdef CONFIG_COMPAT
struct compat_robust_list_head __user *compat_robust_list;
#endif
struct list_head pi_state_list;
struct futex_pi_state *pi_state_cache;
#endif
#ifdef CONFIG_PERF_EVENTS
struct perf_event_context *perf_event_ctxp;
struct mutex perf_event_mutex;
struct list_head perf_event_list;
#endif
#ifdef CONFIG_NUMA
struct mempolicy *mempolicy; /* Protected by alloc_lock */
short il_next;
#endif
atomic_t fs_excl; /* holding fs exclusive resources */
struct rcu_head rcu;
/*
* cache last used pipe for splice
*/
struct pipe_inode_info *splice_pipe;
#ifdef CONFIG_TASK_DELAY_ACCT
struct task_delay_info *delays;
#endif
#ifdef CONFIG_FAULT_INJECTION
int make_it_fail;
#endif
struct prop_local_single dirties;
#ifdef CONFIG_LATENCYTOP
int 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.
*/
unsigned long timer_slack_ns;
unsigned long default_timer_slack_ns;
struct list_head *scm_work_list;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* 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 */
unsigned long stack_start;
};
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版权声明：本文为优快云博主「pointer_y」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.youkuaiyun.com/pointer_y/article/details/54292093
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