最終更新:2021-02-16 (火) 14:15:23 (1165d)  

task_struct
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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;

#ifdef CONFIG_SMP
        struct llist_node wake_entry;
        int on_cpu;
#endif
        int on_rq;

        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_CGROUP_SCHED
        struct task_group *sched_task_group;
#endif

#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;
        int nr_cpus_allowed;
        cpumask_t cpus_allowed;

#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 */

#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
        struct sched_info sched_info;
#endif

        struct list_head tasks;
#ifdef CONFIG_SMP
        struct plist_node pushable_tasks;
#endif

        struct mm_struct *mm, *active_mm;
#ifdef CONFIG_COMPAT_BRK
        unsigned brk_randomized:1;
#endif
#if defined(SPLIT_RSS_COUNTING)
        struct task_rss_stat    rss_stat;
#endif
/* task state */
        int exit_state;
        int exit_code, exit_signal;
        int pdeath_signal;  /*  The signal sent when the parent dies  */
        unsigned int jobctl;    /* JOBCTL_*, siglock protected */
        /* ??? */
        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;

        /* task may not gain privileges */
        unsigned no_new_privs:1;

        /* Revert to default priority/policy when forking */
        unsigned sched_reset_on_fork:1;
        unsigned sched_contributes_to_load: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 __rcu *real_parent; /* real parent process */
        struct task_struct __rcu *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;

        /* 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;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
        cputime_t prev_utime, prev_stime;
#endif
        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 __rcu *real_cred; /* objective and real subjective task
                                         * credentials (COW) */
        const struct cred __rcu *cred;  /* effective (overridable) subjective task
                                         * credentials (COW) */
        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 */
        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 callback_head *task_works;

        struct audit_context *audit_context;
#ifdef CONFIG_AUDITSYSCALL
        kuid_t loginuid;
        unsigned int sessionid;
#endif
        struct seccomp 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;

        /* Protection of the PI data structures: */
        raw_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;
        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
#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_list *bio_list;

#ifdef CONFIG_BLOCK
/* stack plugging */
        struct blk_plug *plug;
#endif

/* 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 */
        seqcount_t mems_allowed_seq;    /* Seqence no to catch updates */
        int cpuset_mem_spread_rotor;
        int cpuset_slab_spread_rotor;
#endif
#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_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[perf_nr_task_contexts];
        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;
        short pref_node_fork;
#endif
        struct rcu_head rcu;

        /*
         * cache last used pipe for splice
         */
        struct pipe_inode_info *splice_pipe;

        struct page_frag task_frag;

#ifdef  CONFIG_TASK_DELAY_ACCT
        struct task_delay_info *delays;
#endif
#ifdef CONFIG_FAULT_INJECTION
        int make_it_fail;
#endif
        /*
         * when (nr_dirtied >= nr_dirtied_pause), it's time to call
         * balance_dirty_pages() for some dirty throttling pause
         */
        int nr_dirtied;
        int nr_dirtied_pause;
        unsigned long dirty_paused_when; /* start of a write-and-pause period */

#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;

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        /* Index of current stored address 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 and counter of trace recursion */
        unsigned long trace_recursion;
#endif /* CONFIG_TRACING */
#ifdef CONFIG_MEMCG /* 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 nr_pages; /* uncharged usage */
                unsigned long memsw_nr_pages; /* uncharged mem+swap usage */
        } memcg_batch;
#endif
#ifdef CONFIG_HAVE_HW_BREAKPOINT
        atomic_t ptrace_bp_refcnt;
#endif
#ifdef CONFIG_UPROBES
        struct uprobe_task *utask;
#endif
};

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