sched.h

#ifndef _LINUX_SCHED_H
#define _LINUX_SCHED_H

#include 


struct sched_param {
    int sched_priority;
};

#include   /* for HZ */

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struct exec_domain;
struct futex_pi_state;
struct robust_list_head;
struct bio_list;
struct fs_struct;
struct perf_event_context;
struct blk_plug;

/*
 * List of flags we want to share for kernel threads,
 * if only because they are not used by them anyway.
 */
#define CLONE_KERNEL    (CLONE_FS | CLONE_FILES | CLONE_SIGHAND)

/*
 * These are the constant used to fake the fixed-point load-average
 * counting. Some notes:
 *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
 *    a load-average precision of 10 bits integer + 11 bits fractional
 *  - if you want to count load-averages more often, you need more
 *    precision, or rounding will get you. With 2-second counting freq,
 *    the EXP_n values would be 1981, 2034 and 2043 if still using only
 *    11 bit fractions.
 */
extern unsigned long avenrun[];     /* Load averages */
extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);

#define FSHIFT      11      /* nr of bits of precision */
#define FIXED_1     (1<
#define LOAD_FREQ   (5*HZ+1)    /* 5 sec intervals */
#define EXP_1       1884        /* 1/exp(5sec/1min) as fixed-point */
#define EXP_5       2014        /* 1/exp(5sec/5min) */
#define EXP_15      2037        /* 1/exp(5sec/15min) */

#define CALC_LOAD(load,exp,n) \
    load *= exp; \
    load += n*(FIXED_1-exp); \
    load >>= FSHIFT;

extern unsigned long total_forks;
extern int nr_threads;
DECLARE_PER_CPU(unsigned long, process_counts);
extern int nr_processes(void);
extern unsigned long nr_running(void);
extern unsigned long nr_iowait(void);
extern unsigned long nr_iowait_cpu(int cpu);
extern unsigned long this_cpu_load(void);


extern void calc_global_load(unsigned long ticks);
extern void update_cpu_load_nohz(void);

/* Notifier for when a task gets migrated to a new CPU */
struct task_migration_notifier {
    struct task_struct *task;
    int from_cpu;
    int to_cpu;
};
extern void register_task_migration_notifier(struct notifier_block *n);

extern unsigned long get_parent_ip(unsigned long addr);

extern void dump_cpu_task(int cpu);

struct seq_file;
struct cfs_rq;
struct task_group;
#ifdef CONFIG_SCHED_DEBUG
extern void proc_sched_show_task(struct task_struct *p, struct seq_file *m);
extern void proc_sched_set_task(struct task_struct *p);
extern void
print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
#endif

/*
 * Task state bitmask. NOTE! These bits are also
 * encoded in fs/proc/array.c: get_task_state().
 *
 * We have two separate sets of flags: task->state
 * is about runnability, while task->exit_state are
 * about the task exiting. Confusing, but this way
 * modifying one set can't modify the other one by
 * mistake.
 */
#define TASK_RUNNING        0
#define TASK_INTERRUPTIBLE  1
#define TASK_UNINTERRUPTIBLE    2
#define __TASK_STOPPED      4
#define __TASK_TRACED       8
/* in tsk->exit_state */
#define EXIT_ZOMBIE     16
#define EXIT_DEAD       32
/* in tsk->state again */
#define TASK_DEAD       64
#define TASK_WAKEKILL       128
#define TASK_WAKING     256
#define TASK_PARKED     512
#define TASK_STATE_MAX      1024

#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP"

extern char ___assert_task_state[1 - 2*!!(
        sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1)];

/* Convenience macros for the sake of set_task_state */
#define TASK_KILLABLE       (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
#define TASK_STOPPED        (TASK_WAKEKILL | __TASK_STOPPED)
#define TASK_TRACED     (TASK_WAKEKILL | __TASK_TRACED)

/* Convenience macros for the sake of wake_up */
#define TASK_NORMAL     (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
#define TASK_ALL        (TASK_NORMAL | __TASK_STOPPED | __TASK_TRACED)

/* get_task_state() */
#define TASK_REPORT     (TASK_RUNNING | TASK_INTERRUPTIBLE | \
                 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
                 __TASK_TRACED)

#define task_is_traced(task)    ((task->state & __TASK_TRACED) != 0)
#define task_is_stopped(task)   ((task->state & __TASK_STOPPED) != 0)
#define task_is_dead(task)  ((task)->exit_state != 0)
#define task_is_stopped_or_traced(task) \
            ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
#define task_contributes_to_load(task)  \
                ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
                 (task->flags & PF_FROZEN) == 0)

#define __set_task_state(tsk, state_value)      \
    do { (tsk)->state = (state_value); } while (0)
#define set_task_state(tsk, state_value)        \
    set_mb((tsk)->state, (state_value))

/*
 * set_current_state() includes a barrier so that the write of current->state
 * is correctly serialised wrt the caller's subsequent test of whether to
 * actually sleep:
 *
 *  set_current_state(TASK_UNINTERRUPTIBLE);
 *  if (do_i_need_to_sleep())
 *      schedule();
 *
 * If the caller does not need such serialisation then use __set_current_state()
 */
#define __set_current_state(state_value)            \
    do { current->state = (state_value); } while (0)
#define set_current_state(state_value)      \
    set_mb(current->state, (state_value))

/* Task command name length */
#define TASK_COMM_LEN 16

#include 

/*
 * This serializes "schedule()" and also protects
 * the run-queue from deletions/modifications (but
 * _adding_ to the beginning of the run-queue has
 * a separate lock).
 */
extern rwlock_t tasklist_lock;
extern spinlock_t mmlist_lock;

struct task_struct;

#ifdef CONFIG_PROVE_RCU
extern int lockdep_tasklist_lock_is_held(void);
#endif /* #ifdef CONFIG_PROVE_RCU */

extern void sched_init(void);
extern void sched_init_smp(void);
extern asmlinkage void schedule_tail(struct task_struct *prev);
extern void init_idle(struct task_struct *idle, int cpu);
extern void init_idle_bootup_task(struct task_struct *idle);

extern int runqueue_is_locked(int cpu);

#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
extern void nohz_balance_enter_idle(int cpu);
extern void set_cpu_sd_state_idle(void);
extern int get_nohz_timer_target(void);
#else
static inline void nohz_balance_enter_idle(int cpu) { }
static inline void set_cpu_sd_state_idle(void) { }
#endif

/*
 * Only dump TASK_* tasks. (0 for all tasks)
 */
extern void show_state_filter(unsigned long state_filter);

static inline void show_state(void)
{
    show_state_filter(0);
}

extern void show_regs(struct pt_regs *);

/*
 * TASK is a pointer to the task whose backtrace we want to see (or NULL for current
 * task), SP is the stack pointer of the first frame that should be shown in the back
 * trace (or NULL if the entire call-chain of the task should be shown).
 */
extern void show_stack(struct task_struct *task, unsigned long *sp);

#ifdef CONFIG_STACK_SHOW
extern void my_show_stack(struct task_struct *tsk, unsigned long *sp,struct pt_regs *regs, unsigned long addr, unsigned int fsr);
#endif

void io_schedule(void);
long io_schedule_timeout(long timeout);

extern void cpu_init (void);
extern void trap_init(void);
extern void update_process_times(int user);
extern void scheduler_tick(void);

extern void sched_show_task(struct task_struct *p);

#ifdef CONFIG_LOCKUP_DETECTOR
extern void touch_softlockup_watchdog(void);
extern void touch_softlockup_watchdog_sync(void);
extern void touch_all_softlockup_watchdogs(void);
extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
                  void __user *buffer,
                  size_t *lenp, loff_t *ppos);
extern unsigned int  softlockup_panic;
void lockup_detector_init(void);
#else
static inline void touch_softlockup_watchdog(void)
{
}
static inline void touch_softlockup_watchdog_sync(void)
{
}
static inline void touch_all_softlockup_watchdogs(void)
{
}
static inline void lockup_detector_init(void)
{
}
#endif

/* Attach to any functions which should be ignored in wchan output. */
#define __sched     __attribute__((__section__(".sched.text")))

/* Linker adds these: start and end of __sched functions */
extern char __sched_text_start[], __sched_text_end[];

/* Is this address in the __sched functions? */
extern int in_sched_functions(unsigned long addr);

#define MAX_SCHEDULE_TIMEOUT    LONG_MAX
extern signed long schedule_timeout(signed long timeout);
extern signed long schedule_timeout_interruptible(signed long timeout);
extern signed long schedule_timeout_killable(signed long timeout);
extern signed long schedule_timeout_uninterruptible(signed long timeout);
asmlinkage void schedule(void);
extern void schedule_preempt_disabled(void);

struct nsproxy;
struct user_namespace;

#ifdef CONFIG_MMU
extern void arch_pick_mmap_layout(struct mm_struct *mm);
extern unsigned long
arch_get_unmapped_area(struct file *, unsigned long, unsigned long,
               unsigned long, unsigned long);
extern unsigned long
arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
              unsigned long len, unsigned long pgoff,
              unsigned long flags);
extern void arch_unmap_area(struct mm_struct *, unsigned long);
extern void arch_unmap_area_topdown(struct mm_struct *, unsigned long);
#else
static inline void arch_pick_mmap_layout(struct mm_struct *mm) {}
#endif


extern void set_dumpable(struct mm_struct *mm, int value);
extern int get_dumpable(struct mm_struct *mm);

/* mm flags */
/* dumpable bits */
#define MMF_DUMPABLE      0  /* core dump is permitted */
#define MMF_DUMP_SECURELY 1  /* core file is readable only by root */

#define MMF_DUMPABLE_BITS 2
#define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)

/* coredump filter bits */
#define MMF_DUMP_ANON_PRIVATE   2
#define MMF_DUMP_ANON_SHARED    3
#define MMF_DUMP_MAPPED_PRIVATE 4
#define MMF_DUMP_MAPPED_SHARED  5
#define MMF_DUMP_ELF_HEADERS    6
#define MMF_DUMP_HUGETLB_PRIVATE 7
#define MMF_DUMP_HUGETLB_SHARED  8

#define MMF_DUMP_FILTER_SHIFT   MMF_DUMPABLE_BITS
#define MMF_DUMP_FILTER_BITS    7
#define MMF_DUMP_FILTER_MASK \
    (((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
#define MMF_DUMP_FILTER_DEFAULT \
    ((1 << MMF_DUMP_ANON_PRIVATE) | (1 << MMF_DUMP_ANON_SHARED) |\
     (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)

#ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
# define MMF_DUMP_MASK_DEFAULT_ELF  (1 << MMF_DUMP_ELF_HEADERS)
#else
# define MMF_DUMP_MASK_DEFAULT_ELF  0
#endif
                    /* leave room for more dump flags */
#define MMF_VM_MERGEABLE    16  /* KSM may merge identical pages */
#define MMF_VM_HUGEPAGE     17  /* set when VM_HUGEPAGE is set on vma */
#define MMF_EXE_FILE_CHANGED    18  /* see prctl_set_mm_exe_file() */

#define MMF_HAS_UPROBES     19  /* has uprobes */
#define MMF_RECALC_UPROBES  20  /* MMF_HAS_UPROBES can be wrong */

#define MMF_INIT_MASK       (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)

struct sighand_struct {
    atomic_t        count;
    struct k_sigaction  action[_NSIG];
    spinlock_t      siglock;
    wait_queue_head_t   signalfd_wqh;
};

struct pacct_struct {
    int         ac_flag;
    long            ac_exitcode;
    unsigned long       ac_mem;
    cputime_t       ac_utime, ac_stime;
    unsigned long       ac_minflt, ac_majflt;
};

struct cpu_itimer {
    cputime_t expires;
    cputime_t incr;
    u32 error;
    u32 incr_error;
};

/**
 * struct cputime - snaphsot of system and user cputime
 * @utime: time spent in user mode
 * @stime: time spent in system mode
 *
 * Gathers a generic snapshot of user and system time.
 */
struct cputime {
    cputime_t utime;
    cputime_t stime;
};

/**
 * struct task_cputime - collected CPU time counts
 * @utime:      time spent in user mode, in &cputime_t units
 * @stime:      time spent in kernel mode, in &cputime_t units
 * @sum_exec_runtime:   total time spent on the CPU, in nanoseconds
 *
 * This is an extension of struct cputime that includes the total runtime
 * spent by the task from the scheduler point of view.
 *
 * As a result, this structure groups together three kinds of CPU time
 * that are tracked for threads and thread groups.  Most things considering
 * CPU time want to group these counts together and treat all three
 * of them in parallel.
 */
struct task_cputime {
    cputime_t utime;
    cputime_t stime;
    unsigned long long sum_exec_runtime;
};
/* Alternate field names when used to cache expirations. */
#define prof_exp    stime
#define virt_exp    utime
#define sched_exp   sum_exec_runtime

#define INIT_CPUTIME    \
    (struct task_cputime) {                 \
        .utime = 0,                 \
        .stime = 0,                 \
        .sum_exec_runtime = 0,              \
    }

/*
 * Disable preemption until the scheduler is running.
 * Reset by start_kernel()->sched_init()->init_idle().
 *
 * We include PREEMPT_ACTIVE to avoid cond_resched() from working
 * before the scheduler is active -- see should_resched().
 */
#define INIT_PREEMPT_COUNT  (1 + PREEMPT_ACTIVE)

/**
 * struct thread_group_cputimer - thread group interval timer counts
 * @cputime:        thread group interval timers.
 * @running:        non-zero when there are timers running and
 *          @cputime receives updates.
 * @lock:       lock for fields in this struct.
 *
 * This structure contains the version of task_cputime, above, that is
 * used for thread group CPU timer calculations.
 */
struct thread_group_cputimer {
    struct task_cputime cputime;
    int running;
    raw_spinlock_t lock;
};

#include 
struct autogroup;

/*
 * NOTE! "signal_struct" does not have its own
 * locking, because a shared signal_struct always
 * implies a shared sighand_struct, so locking
 * sighand_struct is always a proper superset of
 * the locking of signal_struct.
 */
struct signal_struct {
    atomic_t        sigcnt;
    atomic_t        live;
    int         nr_threads;
    struct list_head    thread_head;

    wait_queue_head_t   wait_chldexit;  /* for wait4() */

    /* current thread group signal load-balancing target: */
    struct task_struct  *curr_target;

    /* shared signal handling: */
    struct sigpending   shared_pending;

    /* thread group exit support */
    int         group_exit_code;
    /* overloaded:
     * - notify group_exit_task when ->count is equal to notify_count
     * - everyone except group_exit_task is stopped during signal delivery
     *   of fatal signals, group_exit_task processes the signal.
     */
    int         notify_count;
    struct task_struct  *group_exit_task;

    /* thread group stop support, overloads group_exit_code too */
    int         group_stop_count;
    unsigned int        flags; /* see SIGNAL_* flags below */

    /*
     * PR_SET_CHILD_SUBREAPER marks a process, like a service
     * manager, to re-parent orphan (double-forking) child processes
     * to this process instead of 'init'. The service manager is
     * able to receive SIGCHLD signals and is able to investigate
     * the process until it calls wait(). All children of this
     * process will inherit a flag if they should look for a
     * child_subreaper process at exit.
     */
    unsigned int        is_child_subreaper:1;
    unsigned int        has_child_subreaper:1;

    /* POSIX.1b Interval Timers */
    int         posix_timer_id;
    struct list_head    posix_timers;

    /* ITIMER_REAL timer for the process */
    struct hrtimer real_timer;
    struct pid *leader_pid;
    ktime_t it_real_incr;

    /*
     * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
     * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
     * values are defined to 0 and 1 respectively
     */
    struct cpu_itimer it[2];

    /*
     * Thread group totals for process CPU timers.
     * See thread_group_cputimer(), et al, for details.
     */
    struct thread_group_cputimer cputimer;

    /* Earliest-expiration cache. */
    struct task_cputime cputime_expires;

    struct list_head cpu_timers[3];

    struct pid *tty_old_pgrp;

    /* boolean value for session group leader */
    int leader;

    struct tty_struct *tty; /* NULL if no tty */

#ifdef CONFIG_SCHED_AUTOGROUP
    struct autogroup *autogroup;
#endif
    /*
     * Cumulative resource counters for dead threads in the group,
     * and for reaped dead child processes forked by this group.
     * Live threads maintain their own counters and add to these
     * in __exit_signal, except for the group leader.
     */
    cputime_t utime, stime, cutime, cstime;
    cputime_t gtime;
    cputime_t cgtime;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
    struct cputime prev_cputime;
#endif
    unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
    unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
    unsigned long inblock, oublock, cinblock, coublock;
    unsigned long maxrss, cmaxrss;
    struct task_io_accounting ioac;

    /*
     * Cumulative ns of schedule CPU time fo dead threads in the
     * group, not including a zombie group leader, (This only differs
     * from jiffies_to_ns(utime + stime) if sched_clock uses something
     * other than jiffies.)
     */
    unsigned long long sum_sched_runtime;

    /*
     * We don't bother to synchronize most readers of this at all,
     * because there is no reader checking a limit that actually needs
     * to get both rlim_cur and rlim_max atomically, and either one
     * alone is a single word that can safely be read normally.
     * getrlimit/setrlimit use task_lock(current->group_leader) to
     * protect this instead of the siglock, because they really
     * have no need to disable irqs.
     */
    struct rlimit rlim[RLIM_NLIMITS];

#ifdef CONFIG_BSD_PROCESS_ACCT
    struct pacct_struct pacct;  /* per-process accounting information */
#endif
#ifdef CONFIG_TASKSTATS
    struct taskstats *stats;
#endif
#ifdef CONFIG_AUDIT
    unsigned audit_tty;
    unsigned audit_tty_log_passwd;
    struct tty_audit_buf *tty_audit_buf;
#endif
#ifdef CONFIG_CGROUPS
    /*
     * group_rwsem prevents new tasks from entering the threadgroup and
     * member tasks from exiting,a more specifically, setting of
     * PF_EXITING.  fork and exit paths are protected with this rwsem
     * using threadgroup_change_begin/end().  Users which require
     * threadgroup to remain stable should use threadgroup_[un]lock()
     * which also takes care of exec path.  Currently, cgroup is the
     * only user.
     */
    struct rw_semaphore group_rwsem;
#endif

    oom_flags_t oom_flags;
    short oom_score_adj;        /* OOM kill score adjustment */
    short oom_score_adj_min;    /* OOM kill score adjustment min value.
                     * Only settable by CAP_SYS_RESOURCE. */

    struct mutex cred_guard_mutex;  /* guard against foreign influences on
                     * credential calculations
                     * (notably. ptrace) */
};

/*
 * Bits in flags field of signal_struct.
 */
#define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */
#define SIGNAL_STOP_CONTINUED   0x00000002 /* SIGCONT since WCONTINUED reap */
#define SIGNAL_GROUP_EXIT   0x00000004 /* group exit in progress */
#define SIGNAL_GROUP_COREDUMP   0x00000008 /* coredump in progress */
/*
 * Pending notifications to parent.
 */
#define SIGNAL_CLD_STOPPED  0x00000010
#define SIGNAL_CLD_CONTINUED    0x00000020
#define SIGNAL_CLD_MASK     (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)

#define SIGNAL_UNKILLABLE   0x00000040 /* for init: ignore fatal signals */

/* If true, all threads except ->group_exit_task have pending SIGKILL */
static inline int signal_group_exit(const struct signal_struct *sig)
{
    return  (sig->flags & SIGNAL_GROUP_EXIT) ||
        (sig->group_exit_task != NULL);
}

/*
 * Some day this will be a full-fledged user tracking system..
 */
struct user_struct {
    atomic_t __count;   /* reference count */
    atomic_t processes; /* How many processes does this user have? */
    atomic_t files;     /* How many open files does this user have? */
    atomic_t sigpending;    /* How many pending signals does this user have? */
#ifdef CONFIG_INOTIFY_USER
    atomic_t inotify_watches; /* How many inotify watches does this user have? */
    atomic_t inotify_devs;  /* How many inotify devs does this user have opened? */
#endif
#ifdef CONFIG_FANOTIFY
    atomic_t fanotify_listeners;
#endif
#ifdef CONFIG_EPOLL
    atomic_long_t epoll_watches; /* The number of file descriptors currently watched */
#endif
#ifdef CONFIG_POSIX_MQUEUE
    /* protected by mq_lock */
    unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */
#endif
    unsigned long locked_shm; /* How many pages of mlocked shm ? */

#ifdef CONFIG_KEYS
    struct key *uid_keyring;    /* UID specific keyring */
    struct key *session_keyring;    /* UID's default session keyring */
#endif

    /* Hash table maintenance information */
    struct hlist_node uidhash_node;
    kuid_t uid;

#ifdef CONFIG_PERF_EVENTS
    atomic_long_t locked_vm;
#endif
};

extern int uids_sysfs_init(void);

extern struct user_struct *find_user(kuid_t);

extern struct user_struct root_user;
#define INIT_USER (&root_user)


struct backing_dev_info;
struct reclaim_state;

#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
struct sched_info {
    /* cumulative counters */
    unsigned long pcount;         /* # of times run on this cpu */
    unsigned long long run_delay; /* time spent waiting on a runqueue */

    /* timestamps */
    unsigned long long last_arrival,/* when we last ran on a cpu */
               last_queued; /* when we were last queued to run */
};
#endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */

#ifdef CONFIG_TASK_DELAY_ACCT
struct task_delay_info {
    spinlock_t  lock;
    unsigned int    flags;  /* Private per-task flags */

    /* For each stat XXX, add following, aligned appropriately
     *
     * struct timespec XXX_start, XXX_end;
     * u64 XXX_delay;
     * u32 XXX_count;
     *
     * Atomicity of updates to XXX_delay, XXX_count protected by
     * single lock above (split into XXX_lock if contention is an issue).
     */

    /*
     * XXX_count is incremented on every XXX operation, the delay
     * associated with the operation is added to XXX_delay.
     * XXX_delay contains the accumulated delay time in nanoseconds.
     */
    struct timespec blkio_start, blkio_end; /* Shared by blkio, swapin */
    u64 blkio_delay;    /* wait for sync block io completion */
    u64 swapin_delay;   /* wait for swapin block io completion */
    u32 blkio_count;    /* total count of the number of sync block */
                /* io operations performed */
    u32 swapin_count;   /* total count of the number of swapin block */
                /* io operations performed */

    struct timespec freepages_start, freepages_end;
    u64 freepages_delay;    /* wait for memory reclaim */
    u32 freepages_count;    /* total count of memory reclaim */
};
#endif  /* CONFIG_TASK_DELAY_ACCT */

static inline int sched_info_on(void)
{
#ifdef CONFIG_SCHEDSTATS
    return 1;
#elif defined(CONFIG_TASK_DELAY_ACCT)
    extern int delayacct_on;
    return delayacct_on;
#else
    return 0;
#endif
}

enum cpu_idle_type {
    CPU_IDLE,
    CPU_NOT_IDLE,
    CPU_NEWLY_IDLE,
    CPU_MAX_IDLE_TYPES
};

/*
 * Increase resolution of cpu_power calculations
 */
#define SCHED_POWER_SHIFT   10
#define SCHED_POWER_SCALE   (1L << SCHED_POWER_SHIFT)

/*
 * sched-domains (multiprocessor balancing) declarations:
 */
#ifdef CONFIG_SMP
#define SD_LOAD_BALANCE     0x0001  /* Do load balancing on this domain. */
#define SD_BALANCE_NEWIDLE  0x0002  /* Balance when about to become idle */
#define SD_BALANCE_EXEC     0x0004  /* Balance on exec */
#define SD_BALANCE_FORK     0x0008  /* Balance on fork, clone */
#define SD_BALANCE_WAKE     0x0010  /* Balance on wakeup */
#define SD_WAKE_AFFINE      0x0020  /* Wake task to waking CPU */
#define SD_SHARE_CPUPOWER   0x0080  /* Domain members share cpu power */
#define SD_SHARE_PKG_RESOURCES  0x0200  /* Domain members share cpu pkg resources */
#define SD_SERIALIZE        0x0400  /* Only a single load balancing instance */
#define SD_ASYM_PACKING     0x0800  /* Place busy groups earlier in the domain */
#define SD_PREFER_SIBLING   0x1000  /* Prefer to place tasks in a sibling domain */
#define SD_OVERLAP      0x2000  /* sched_domains of this level overlap */

extern int __weak arch_sd_sibiling_asym_packing(void);

struct sched_domain_attr {
    int relax_domain_level;
};

#define SD_ATTR_INIT    (struct sched_domain_attr) {    \
    .relax_domain_level = -1,           \
}

extern int sched_domain_level_max;

struct sched_group;

struct sched_domain {
    /* These fields must be setup */
    struct sched_domain *parent;    /* top domain must be null terminated */
    struct sched_domain *child; /* bottom domain must be null terminated */
    struct sched_group *groups; /* the balancing groups of the domain */
    unsigned long min_interval; /* Minimum balance interval ms */
    unsigned long max_interval; /* Maximum balance interval ms */
    unsigned int busy_factor;   /* less balancing by factor if busy */
    unsigned int imbalance_pct; /* No balance until over watermark */
    unsigned int cache_nice_tries;  /* Leave cache hot tasks for # tries */
    unsigned int busy_idx;
    unsigned int idle_idx;
    unsigned int newidle_idx;
    unsigned int wake_idx;
    unsigned int forkexec_idx;
    unsigned int smt_gain;

    int nohz_idle;          /* NOHZ IDLE status */
    int flags;          /* See SD_* */
    int level;

    /* Runtime fields. */
    unsigned long last_balance; /* init to jiffies. units in jiffies */
    unsigned int balance_interval;  /* initialise to 1. units in ms. */
    unsigned int nr_balance_failed; /* initialise to 0 */

    u64 last_update;

#ifdef CONFIG_SCHEDSTATS
    /* load_balance() stats */
    unsigned int lb_count[CPU_MAX_IDLE_TYPES];
    unsigned int lb_failed[CPU_MAX_IDLE_TYPES];
    unsigned int lb_balanced[CPU_MAX_IDLE_TYPES];
    unsigned int lb_imbalance[CPU_MAX_IDLE_TYPES];
    unsigned int lb_gained[CPU_MAX_IDLE_TYPES];
    unsigned int lb_hot_gained[CPU_MAX_IDLE_TYPES];
    unsigned int lb_nobusyg[CPU_MAX_IDLE_TYPES];
    unsigned int lb_nobusyq[CPU_MAX_IDLE_TYPES];

    /* Active load balancing */
    unsigned int alb_count;
    unsigned int alb_failed;
    unsigned int alb_pushed;

    /* SD_BALANCE_EXEC stats */
    unsigned int sbe_count;
    unsigned int sbe_balanced;
    unsigned int sbe_pushed;

    /* SD_BALANCE_FORK stats */
    unsigned int sbf_count;
    unsigned int sbf_balanced;
    unsigned int sbf_pushed;

    /* try_to_wake_up() stats */
    unsigned int ttwu_wake_remote;
    unsigned int ttwu_move_affine;
    unsigned int ttwu_move_balance;
#endif
#ifdef CONFIG_SCHED_DEBUG
    char *name;
#endif
    union {
        void *private;      /* used during construction */
        struct rcu_head rcu;    /* used during destruction */
    };

    unsigned int span_weight;
    /*
     * Span of all CPUs in this domain.
     *
     * NOTE: this field is variable length. (Allocated dynamically
     * by attaching extra space to the end of the structure,
     * depending on how many CPUs the kernel has booted up with)
     */
    unsigned long span[0];
};

static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
{
    return to_cpumask(sd->span);
}

extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
                    struct sched_domain_attr *dattr_new);

/* Allocate an array of sched domains, for partition_sched_domains(). */
cpumask_var_t *alloc_sched_domains(unsigned int ndoms);
void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);

bool cpus_share_cache(int this_cpu, int that_cpu);

#else /* CONFIG_SMP */

struct sched_domain_attr;

static inline void
partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
            struct sched_domain_attr *dattr_new)
{
}

static inline bool cpus_share_cache(int this_cpu, int that_cpu)
{
    return true;
}

#endif  /* !CONFIG_SMP */


struct io_context;          /* See blkdev.h */


#ifdef ARCH_HAS_PREFETCH_SWITCH_STACK
extern void prefetch_stack(struct task_struct *t);
#else
static inline void prefetch_stack(struct task_struct *t) { }
#endif

struct audit_context;       /* See audit.c */
struct mempolicy;
struct pipe_inode_info;
struct uts_namespace;

struct load_weight {
    unsigned long weight, inv_weight;
};

struct sched_avg {
    /*
     * These sums represent an infinite geometric series and so are bound
     * above by 1024/(1-y).  Thus we only need a u32 to store them for for all
     * choices of y < 1-2^(-32)*1024.
     */
    u32 runnable_avg_sum, runnable_avg_period;
    u64 last_runnable_update;
    s64 decay_count;
    unsigned long load_avg_contrib;
};

#ifdef CONFIG_SCHEDSTATS
struct sched_statistics {
    u64         wait_start;
    u64         wait_max;
    u64         wait_count;
    u64         wait_sum;
    u64         iowait_count;
    u64         iowait_sum;

    u64         sleep_start;
    u64         sleep_max;
    s64         sum_sleep_runtime;

    u64         block_start;
    u64         block_max;
    u64         exec_max;
    u64         slice_max;

    u64         nr_migrations_cold;
    u64         nr_failed_migrations_affine;
    u64         nr_failed_migrations_running;
    u64         nr_failed_migrations_hot;
    u64         nr_forced_migrations;

    u64         nr_wakeups;
    u64         nr_wakeups_sync;
    u64         nr_wakeups_migrate;
    u64         nr_wakeups_local;
    u64         nr_wakeups_remote;
    u64         nr_wakeups_affine;
    u64         nr_wakeups_affine_attempts;
    u64         nr_wakeups_passive;
    u64         nr_wakeups_idle;
};
#endif

struct sched_entity {
    struct load_weight  load;       /* for load-balancing */
    struct rb_node      run_node;
    struct list_head    group_node;
    unsigned int        on_rq;

    u64         exec_start;
    u64         sum_exec_runtime;
    u64         vruntime;
    u64         prev_sum_exec_runtime;

    u64         nr_migrations;

#ifdef CONFIG_SCHEDSTATS
    struct sched_statistics statistics;
#endif

#ifdef CONFIG_FAIR_GROUP_SCHED
    struct sched_entity *parent;
    /* rq on which this entity is (to be) queued: */
    struct cfs_rq       *cfs_rq;
    /* rq "owned" by this entity/group: */
    struct cfs_rq       *my_q;
#endif

/*
 * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
 * removed when useful for applications beyond shares distribution (e.g.
 * load-balance).
 */
#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
    /* Per-entity load-tracking */
    struct sched_avg    avg;
#endif
};

struct sched_rt_entity {
    struct list_head run_list;
    unsigned long timeout;
    unsigned long watchdog_stamp;
    unsigned int time_slice;

    struct sched_rt_entity *back;
#ifdef CONFIG_RT_GROUP_SCHED
    struct sched_rt_entity  *parent;
    /* rq on which this entity is (to be) queued: */
    struct rt_rq        *rt_rq;
    /* rq "owned" by this entity/group: */
    struct rt_rq        *my_q;
#endif
};


struct rcu_node;

enum perf_event_task_context {
    perf_invalid_context = -1,
    perf_hw_context = 0,
    perf_sw_context,
    perf_nr_task_contexts,
};

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 */

    /* Used for emulating ABI behavior of previous Linux versions */
    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;
    unsigned sched_contributes_to_load:1;

    unsigned long atomic_flags; /* Flags needing atomic access. */

    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 list_head thread_node;

    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_NATIVE
    struct cputime prev_cputime;
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
    seqlock_t vtime_seqlock;
    unsigned long long vtime_snap;
    enum {
        VTIME_SLEEPING = 0,
        VTIME_USER,
        VTIME_SYS,
    } vtime_snap_whence;
#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
#ifdef CONFIG_NUMA_BALANCING
    int numa_scan_seq;
    int numa_migrate_seq;
    unsigned int numa_scan_period;
    u64 node_stamp;         /* migration stamp  */
    struct callback_head numa_work;
#endif /* CONFIG_NUMA_BALANCING */

    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;
    unsigned int memcg_kmem_skip_account;
#endif
#ifdef CONFIG_HAVE_HW_BREAKPOINT
    atomic_t ptrace_bp_refcnt;
#endif
#ifdef CONFIG_UPROBES
    struct uprobe_task *utask;
#endif
#if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
    unsigned int    sequential_io;
    unsigned int    sequential_io_avg;
#endif
};

/* Future-safe accessor for struct task_struct's cpus_allowed. */
#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)

#ifdef CONFIG_NUMA_BALANCING
extern void task_numa_fault(int node, int pages, bool migrated);
extern void set_numabalancing_state(bool enabled);
#else
static inline void task_numa_fault(int node, int pages, bool migrated)
{
}
static inline void set_numabalancing_state(bool enabled)
{
}
#endif

static inline struct pid *task_pid(struct task_struct *task)
{
    return task->pids[PIDTYPE_PID].pid;
}

static inline struct pid *task_tgid(struct task_struct *task)
{
    return task->group_leader->pids[PIDTYPE_PID].pid;
}

/*
 * Without tasklist or rcu lock it is not safe to dereference
 * the result of task_pgrp/task_session even if task == current,
 * we can race with another thread doing sys_setsid/sys_setpgid.
 */
static inline struct pid *task_pgrp(struct task_struct *task)
{
    return task->group_leader->pids[PIDTYPE_PGID].pid;
}

static inline struct pid *task_session(struct task_struct *task)
{
    return task->group_leader->pids[PIDTYPE_SID].pid;
}

struct pid_namespace;

/*
 * the helpers to get the task's different pids as they are seen
 * from various namespaces
 *
 * task_xid_nr()     : global id, i.e. the id seen from the init namespace;
 * task_xid_vnr()    : virtual id, i.e. the id seen from the pid namespace of
 *                     current.
 * task_xid_nr_ns()  : id seen from the ns specified;
 *
 * set_task_vxid()   : assigns a virtual id to a task;
 *
 * see also pid_nr() etc in include/linux/pid.h
 */
pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
            struct pid_namespace *ns);

static inline pid_t task_pid_nr(struct task_struct *tsk)
{
    return tsk->pid;
}

static inline pid_t task_pid_nr_ns(struct task_struct *tsk,
                    struct pid_namespace *ns)
{
    return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns);
}

static inline pid_t task_pid_vnr(struct task_struct *tsk)
{
    return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL);
}


static inline pid_t task_tgid_nr(struct task_struct *tsk)
{
    return tsk->tgid;
}

pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns);

static inline pid_t task_tgid_vnr(struct task_struct *tsk)
{
    return pid_vnr(task_tgid(tsk));
}


static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk,
                    struct pid_namespace *ns)
{
    return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns);
}

static inline pid_t task_pgrp_vnr(struct task_struct *tsk)
{
    return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL);
}


static inline pid_t task_session_nr_ns(struct task_struct *tsk,
                    struct pid_namespace *ns)
{
    return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns);
}

static inline pid_t task_session_vnr(struct task_struct *tsk)
{
    return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL);
}

/* obsolete, do not use */
static inline pid_t task_pgrp_nr(struct task_struct *tsk)
{
    return task_pgrp_nr_ns(tsk, &init_pid_ns);
}

/**
 * pid_alive - check that a task structure is not stale
 * @p: Task structure to be checked.
 *
 * Test if a process is not yet dead (at most zombie state)
 * If pid_alive fails, then pointers within the task structure
 * can be stale and must not be dereferenced.
 */
static inline int pid_alive(struct task_struct *p)
{
    return p->pids[PIDTYPE_PID].pid != NULL;
}

/**
 * is_global_init - check if a task structure is init
 * @tsk: Task structure to be checked.
 *
 * Check if a task structure is the first user space task the kernel created.
 */
static inline int is_global_init(struct task_struct *tsk)
{
    return tsk->pid == 1;
}

extern struct pid *cad_pid;

extern void free_task(struct task_struct *tsk);
#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)

extern void __put_task_struct(struct task_struct *t);

static inline void put_task_struct(struct task_struct *t)
{
    if (atomic_dec_and_test(&t->usage))
        __put_task_struct(t);
}

#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
extern void task_cputime(struct task_struct *t,
             cputime_t *utime, cputime_t *stime);
extern void task_cputime_scaled(struct task_struct *t,
                cputime_t *utimescaled, cputime_t *stimescaled);
extern cputime_t task_gtime(struct task_struct *t);
#else
static inline void task_cputime(struct task_struct *t,
                cputime_t *utime, cputime_t *stime)
{
    if (utime)
        *utime = t->utime;
    if (stime)
        *stime = t->stime;
}

static inline void task_cputime_scaled(struct task_struct *t,
                       cputime_t *utimescaled,
                       cputime_t *stimescaled)
{
    if (utimescaled)
        *utimescaled = t->utimescaled;
    if (stimescaled)
        *stimescaled = t->stimescaled;
}

static inline cputime_t task_gtime(struct task_struct *t)
{
    return t->gtime;
}
#endif
extern void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);

extern int task_free_register(struct notifier_block *n);
extern int task_free_unregister(struct notifier_block *n);

/*
 * Per process flags
 */
#define PF_EXITING  0x00000004  /* getting shut down */
#define PF_EXITPIDONE   0x00000008  /* pi exit done on shut down */
#define PF_VCPU     0x00000010  /* I'm a virtual CPU */
#define PF_WQ_WORKER    0x00000020  /* I'm a workqueue worker */
#define PF_FORKNOEXEC   0x00000040  /* forked but didn't exec */
#define PF_MCE_PROCESS  0x00000080      /* process policy on mce errors */
#define PF_SUPERPRIV    0x00000100  /* used super-user privileges */
#define PF_DUMPCORE 0x00000200  /* dumped core */
#define PF_SIGNALED 0x00000400  /* killed by a signal */
#define PF_MEMALLOC 0x00000800  /* Allocating memory */
#define PF_NPROC_EXCEEDED 0x00001000    /* set_user noticed that RLIMIT_NPROC was exceeded */
#define PF_USED_MATH    0x00002000  /* if unset the fpu must be initialized before use */
#define PF_USED_ASYNC   0x00004000  /* used async_schedule*(), used by module init */
#define PF_NOFREEZE 0x00008000  /* this thread should not be frozen */
#define PF_FROZEN   0x00010000  /* frozen for system suspend */
#define PF_FSTRANS  0x00020000  /* inside a filesystem transaction */
#define PF_KSWAPD   0x00040000  /* I am kswapd */
#define PF_MEMALLOC_NOIO 0x00080000 /* Allocating memory without IO involved */
#define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */
#define PF_KTHREAD  0x00200000  /* I am a kernel thread */
#define PF_RANDOMIZE    0x00400000  /* randomize virtual address space */
#define PF_SWAPWRITE    0x00800000  /* Allowed to write to swap */
#define PF_SPREAD_PAGE  0x01000000  /* Spread page cache over cpuset */
#define PF_SPREAD_SLAB  0x02000000  /* Spread some slab caches over cpuset */
#define PF_NO_SETAFFINITY 0x04000000    /* Userland is not allowed to meddle with cpus_allowed */
#define PF_MCE_EARLY    0x08000000      /* Early kill for mce process policy */
#define PF_MEMPOLICY    0x10000000  /* Non-default NUMA mempolicy */
#define PF_MUTEX_TESTER 0x20000000  /* Thread belongs to the rt mutex tester */
#define PF_FREEZER_SKIP 0x40000000  /* Freezer should not count it as freezable */

/*
 * Only the _current_ task can read/write to tsk->flags, but other
 * tasks can access tsk->flags in readonly mode for example
 * with tsk_used_math (like during threaded core dumping).
 * There is however an exception to this rule during ptrace
 * or during fork: the ptracer task is allowed to write to the
 * child->flags of its traced child (same goes for fork, the parent
 * can write to the child->flags), because we're guaranteed the
 * child is not running and in turn not changing child->flags
 * at the same time the parent does it.
 */
#define clear_stopped_child_used_math(child) do { (child)->flags &= ~PF_USED_MATH; } while (0)
#define set_stopped_child_used_math(child) do { (child)->flags |= PF_USED_MATH; } while (0)
#define clear_used_math() clear_stopped_child_used_math(current)
#define set_used_math() set_stopped_child_used_math(current)
#define conditional_stopped_child_used_math(condition, child) \
    do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
#define conditional_used_math(condition) \
    conditional_stopped_child_used_math(condition, current)
#define copy_to_stopped_child_used_math(child) \
    do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
/* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
#define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
#define used_math() tsk_used_math(current)

/* __GFP_IO isn't allowed if PF_MEMALLOC_NOIO is set in current->flags */
static inline gfp_t memalloc_noio_flags(gfp_t flags)
{
    if (unlikely(current->flags & PF_MEMALLOC_NOIO))
        flags &= ~__GFP_IO;
    return flags;
}

static inline unsigned int memalloc_noio_save(void)
{
    unsigned int flags = current->flags & PF_MEMALLOC_NOIO;
    current->flags |= PF_MEMALLOC_NOIO;
    return flags;
}

static inline void memalloc_noio_restore(unsigned int flags)
{
    current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
}

/* Per-process atomic flags. */
#define PFA_NO_NEW_PRIVS 0x00000001 /* May not gain new privileges. */

static inline bool task_no_new_privs(struct task_struct *p)
{
    return test_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
}

static inline void task_set_no_new_privs(struct task_struct *p)
{
    set_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
}

/*
 * task->jobctl flags
 */
#define JOBCTL_STOP_SIGMASK 0xffff  /* signr of the last group stop */

#define JOBCTL_STOP_DEQUEUED_BIT 16 /* stop signal dequeued */
#define JOBCTL_STOP_PENDING_BIT 17  /* task should stop for group stop */
#define JOBCTL_STOP_CONSUME_BIT 18  /* consume group stop count */
#define JOBCTL_TRAP_STOP_BIT    19  /* trap for STOP */
#define JOBCTL_TRAP_NOTIFY_BIT  20  /* trap for NOTIFY */
#define JOBCTL_TRAPPING_BIT 21  /* switching to TRACED */
#define JOBCTL_LISTENING_BIT    22  /* ptracer is listening for events */

#define JOBCTL_STOP_DEQUEUED    (1 << JOBCTL_STOP_DEQUEUED_BIT)
#define JOBCTL_STOP_PENDING (1 << JOBCTL_STOP_PENDING_BIT)
#define JOBCTL_STOP_CONSUME (1 << JOBCTL_STOP_CONSUME_BIT)
#define JOBCTL_TRAP_STOP    (1 << JOBCTL_TRAP_STOP_BIT)
#define JOBCTL_TRAP_NOTIFY  (1 << JOBCTL_TRAP_NOTIFY_BIT)
#define JOBCTL_TRAPPING     (1 << JOBCTL_TRAPPING_BIT)
#define JOBCTL_LISTENING    (1 << JOBCTL_LISTENING_BIT)

#define JOBCTL_TRAP_MASK    (JOBCTL_TRAP_STOP | JOBCTL_TRAP_NOTIFY)
#define JOBCTL_PENDING_MASK (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK)

extern bool task_set_jobctl_pending(struct task_struct *task,
                    unsigned int mask);
extern void task_clear_jobctl_trapping(struct task_struct *task);
extern void task_clear_jobctl_pending(struct task_struct *task,
                      unsigned int mask);

#ifdef CONFIG_PREEMPT_RCU

#define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */
#define RCU_READ_UNLOCK_NEED_QS (1 << 1) /* RCU core needs CPU response. */

static inline void rcu_copy_process(struct task_struct *p)
{
    p->rcu_read_lock_nesting = 0;
    p->rcu_read_unlock_special = 0;
#ifdef CONFIG_TREE_PREEMPT_RCU
    p->rcu_blocked_node = NULL;
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
#ifdef CONFIG_RCU_BOOST
    p->rcu_boost_mutex = NULL;
#endif /* #ifdef CONFIG_RCU_BOOST */
    INIT_LIST_HEAD(&p->rcu_node_entry);
}

#else

static inline void rcu_copy_process(struct task_struct *p)
{
}

#endif

static inline void tsk_restore_flags(struct task_struct *task,
                unsigned long orig_flags, unsigned long flags)
{
    task->flags &= ~flags;
    task->flags |= orig_flags & flags;
}

#ifdef CONFIG_SMP
extern void do_set_cpus_allowed(struct task_struct *p,
                   const struct cpumask *new_mask);

extern int set_cpus_allowed_ptr(struct task_struct *p,
                const struct cpumask *new_mask);
#else
static inline void do_set_cpus_allowed(struct task_struct *p,
                      const struct cpumask *new_mask)
{
}
static inline int set_cpus_allowed_ptr(struct task_struct *p,
                       const struct cpumask *new_mask)
{
    if (!cpumask_test_cpu(0, new_mask))
        return -EINVAL;
    return 0;
}
#endif

#ifdef CONFIG_NO_HZ_COMMON
void calc_load_enter_idle(void);
void calc_load_exit_idle(void);
#else
static inline void calc_load_enter_idle(void) { }
static inline void calc_load_exit_idle(void) { }
#endif /* CONFIG_NO_HZ_COMMON */

#ifndef CONFIG_CPUMASK_OFFSTACK
static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
{
    return set_cpus_allowed_ptr(p, &new_mask);
}
#endif

/*
 * Do not use outside of architecture code which knows its limitations.
 *
 * sched_clock() has no promise of monotonicity or bounded drift between
 * CPUs, use (which you should not) requires disabling IRQs.
 *
 * Please use one of the three interfaces below.
 */
extern unsigned long long notrace sched_clock(void);
/*
 * See the comment in kernel/sched/clock.c
 */
extern u64 cpu_clock(int cpu);
extern u64 local_clock(void);
extern u64 sched_clock_cpu(int cpu);


extern void sched_clock_init(void);

#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
static inline void sched_clock_tick(void)
{
}

static inline void sched_clock_idle_sleep_event(void)
{
}

static inline void sched_clock_idle_wakeup_event(u64 delta_ns)
{
}
#else
/*
 * Architectures can set this to 1 if they have specified
 * CONFIG_HAVE_UNSTABLE_SCHED_CLOCK in their arch Kconfig,
 * but then during bootup it turns out that sched_clock()
 * is reliable after all:
 */
extern int sched_clock_stable;

extern void sched_clock_tick(void);
extern void sched_clock_idle_sleep_event(void);
extern void sched_clock_idle_wakeup_event(u64 delta_ns);
#endif

#ifdef CONFIG_IRQ_TIME_ACCOUNTING
/*
 * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
 * The reason for this explicit opt-in is not to have perf penalty with
 * slow sched_clocks.
 */
extern void enable_sched_clock_irqtime(void);
extern void disable_sched_clock_irqtime(void);
#else
static inline void enable_sched_clock_irqtime(void) {}
static inline void disable_sched_clock_irqtime(void) {}
#endif

extern unsigned long long
task_sched_runtime(struct task_struct *task);

/* sched_exec is called by processes performing an exec */
#ifdef CONFIG_SMP
extern void sched_exec(void);
#else
#define sched_exec()   {}
#endif

extern void sched_clock_idle_sleep_event(void);
extern void sched_clock_idle_wakeup_event(u64 delta_ns);

#ifdef CONFIG_HOTPLUG_CPU
extern void idle_task_exit(void);
#else
static inline void idle_task_exit(void) {}
#endif

#if defined(CONFIG_NO_HZ_COMMON) && defined(CONFIG_SMP)
extern void wake_up_nohz_cpu(int cpu);
#else
static inline void wake_up_nohz_cpu(int cpu) { }
#endif

#ifdef CONFIG_NO_HZ_FULL
extern bool sched_can_stop_tick(void);
extern u64 scheduler_tick_max_deferment(void);
#else
static inline bool sched_can_stop_tick(void) { return false; }
#endif

#ifdef CONFIG_SCHED_AUTOGROUP
extern void sched_autogroup_create_attach(struct task_struct *p);
extern void sched_autogroup_detach(struct task_struct *p);
extern void sched_autogroup_fork(struct signal_struct *sig);
extern void sched_autogroup_exit(struct signal_struct *sig);
#ifdef CONFIG_PROC_FS
extern void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m);
extern int proc_sched_autogroup_set_nice(struct task_struct *p, int nice);
#endif
#else
static inline void sched_autogroup_create_attach(struct task_struct *p) { }
static inline void sched_autogroup_detach(struct task_struct *p) { }
static inline void sched_autogroup_fork(struct signal_struct *sig) { }
static inline void sched_autogroup_exit(struct signal_struct *sig) { }
#endif

extern bool yield_to(struct task_struct *p, bool preempt);
extern void set_user_nice(struct task_struct *p, long nice);
extern int task_prio(const struct task_struct *p);
extern int task_nice(const struct task_struct *p);
extern int can_nice(const struct task_struct *p, const int nice);
extern int task_curr(const struct task_struct *p);
extern int idle_cpu(int cpu);
extern int sched_setscheduler(struct task_struct *, int,
                  const struct sched_param *);
extern int sched_setscheduler_nocheck(struct task_struct *, int,
                      const struct sched_param *);
extern struct task_struct *idle_task(int cpu);
/**
 * is_idle_task - is the specified task an idle task?
 * @p: the task in question.
 */
static inline bool is_idle_task(const struct task_struct *p)
{
    return p->pid == 0;
}
extern struct task_struct *curr_task(int cpu);
extern void set_curr_task(int cpu, struct task_struct *p);

void yield(void);

/*
 * The default (Linux) execution domain.
 */
extern struct exec_domain   default_exec_domain;

union thread_union {
    struct thread_info thread_info;
    unsigned long stack[THREAD_SIZE/sizeof(long)];
};

#ifndef __HAVE_ARCH_KSTACK_END
static inline int kstack_end(void *addr)
{
    /* Reliable end of stack detection:
     * Some APM bios versions misalign the stack
     */
    return !(((unsigned long)addr+sizeof(void*)-1) & (THREAD_SIZE-sizeof(void*)));
}
#endif

extern union thread_union init_thread_union;
extern struct task_struct init_task;

extern struct   mm_struct init_mm;

extern struct pid_namespace init_pid_ns;

/*
 * find a task by one of its numerical ids
 *
 * find_task_by_pid_ns():
 *      finds a task by its pid in the specified namespace
 * find_task_by_vpid():
 *      finds a task by its virtual pid
 *
 * see also find_vpid() etc in include/linux/pid.h
 */

extern struct task_struct *find_task_by_vpid(pid_t nr);
extern struct task_struct *find_task_by_pid_ns(pid_t nr,
        struct pid_namespace *ns);

extern void __set_special_pids(struct pid *pid);

/* per-UID process charging. */
extern struct user_struct * alloc_uid(kuid_t);
static inline struct user_struct *get_uid(struct user_struct *u)
{
    atomic_inc(&u->__count);
    return u;
}
extern void free_uid(struct user_struct *);

#include 

extern void xtime_update(unsigned long ticks);

extern int wake_up_state(struct task_struct *tsk, unsigned int state);
extern int wake_up_process(struct task_struct *tsk);
extern void wake_up_new_task(struct task_struct *tsk);
#ifdef CONFIG_SMP
 extern void kick_process(struct task_struct *tsk);
#else
 static inline void kick_process(struct task_struct *tsk) { }
#endif
extern void sched_fork(struct task_struct *p);
extern void sched_dead(struct task_struct *p);

extern void proc_caches_init(void);
extern void flush_signals(struct task_struct *);
extern void __flush_signals(struct task_struct *);
extern void ignore_signals(struct task_struct *);
extern void flush_signal_handlers(struct task_struct *, int force_default);
extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);

static inline int dequeue_signal_lock(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
{
    unsigned long flags;
    int ret;

    spin_lock_irqsave(&tsk->sighand->siglock, flags);
    ret = dequeue_signal(tsk, mask, info);
    spin_unlock_irqrestore(&tsk->sighand->siglock, flags);

    return ret;
}

extern void block_all_signals(int (*notifier)(void *priv), void *priv,
                  sigset_t *mask);
extern void unblock_all_signals(void);
extern void release_task(struct task_struct * p);
extern int send_sig_info(int, struct siginfo *, struct task_struct *);
extern int force_sigsegv(int, struct task_struct *);
extern int force_sig_info(int, struct siginfo *, struct task_struct *);
extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
extern int kill_pid_info_as_cred(int, struct siginfo *, struct pid *,
                const struct cred *, u32);
extern int kill_pgrp(struct pid *pid, int sig, int priv);
extern int kill_pid(struct pid *pid, int sig, int priv);
extern int kill_proc_info(int, struct siginfo *, pid_t);
extern __must_check bool do_notify_parent(struct task_struct *, int);
extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
extern void force_sig(int, struct task_struct *);
extern int send_sig(int, struct task_struct *, int);
extern int zap_other_threads(struct task_struct *p);
extern struct sigqueue *sigqueue_alloc(void);
extern void sigqueue_free(struct sigqueue *);
extern int send_sigqueue(struct sigqueue *,  struct task_struct *, int group);
extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);

static inline void restore_saved_sigmask(void)
{
    if (test_and_clear_restore_sigmask())
        __set_current_blocked(¤t->saved_sigmask);
}

static inline sigset_t *sigmask_to_save(void)
{
    sigset_t *res = ¤t->blocked;
    if (unlikely(test_restore_sigmask()))
        res = ¤t->saved_sigmask;
    return res;
}

static inline int kill_cad_pid(int sig, int priv)
{
    return kill_pid(cad_pid, sig, priv);
}

/* These can be the second arg to send_sig_info/send_group_sig_info.  */
#define SEND_SIG_NOINFO ((struct siginfo *) 0)
#define SEND_SIG_PRIV   ((struct siginfo *) 1)
#define SEND_SIG_FORCED ((struct siginfo *) 2)

/*
 * True if we are on the alternate signal stack.
 */
static inline int on_sig_stack(unsigned long sp)
{
#ifdef CONFIG_STACK_GROWSUP
    return sp >= current->sas_ss_sp &&
        sp - current->sas_ss_sp < current->sas_ss_size;
#else
    return sp > current->sas_ss_sp &&
        sp - current->sas_ss_sp <= current->sas_ss_size;
#endif
}

static inline int sas_ss_flags(unsigned long sp)
{
    return (current->sas_ss_size == 0 ? SS_DISABLE
        : on_sig_stack(sp) ? SS_ONSTACK : 0);
}

static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
{
    if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
#ifdef CONFIG_STACK_GROWSUP
        return current->sas_ss_sp;
#else
        return current->sas_ss_sp + current->sas_ss_size;
#endif
    return sp;
}

/*
 * Routines for handling mm_structs
 */
extern struct mm_struct * mm_alloc(void);

/* mmdrop drops the mm and the page tables */
extern void __mmdrop(struct mm_struct *);
static inline void mmdrop(struct mm_struct * mm)
{
    if (unlikely(atomic_dec_and_test(&mm->mm_count)))
        __mmdrop(mm);
}

/* mmput gets rid of the mappings and all user-space */
extern void mmput(struct mm_struct *);
/* Grab a reference to a task's mm, if it is not already going away */
extern struct mm_struct *get_task_mm(struct task_struct *task);
/*
 * Grab a reference to a task's mm, if it is not already going away
 * and ptrace_may_access with the mode parameter passed to it
 * succeeds.
 */
extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode);
/* Remove the current tasks stale references to the old mm_struct */
extern void mm_release(struct task_struct *, struct mm_struct *);
/* Allocate a new mm structure and copy contents from tsk->mm */
extern struct mm_struct *dup_mm(struct task_struct *tsk);

extern int copy_thread(unsigned long, unsigned long, unsigned long,
            struct task_struct *);
extern void flush_thread(void);
extern void exit_thread(void);

extern void exit_files(struct task_struct *);
extern void __cleanup_sighand(struct sighand_struct *);

extern void exit_itimers(struct signal_struct *);
extern void flush_itimer_signals(void);

extern void do_group_exit(int);

extern int allow_signal(int);
extern int disallow_signal(int);

extern int do_execve(const char *,
             const char __user * const __user *,
             const char __user * const __user *);
extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
struct task_struct *fork_idle(int);
extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);

extern void set_task_comm(struct task_struct *tsk, char *from);
extern char *get_task_comm(char *to, struct task_struct *tsk);

#ifdef CONFIG_SMP
void scheduler_ipi(void);
extern unsigned long wait_task_inactive(struct task_struct *, long match_state);
#else
static inline void scheduler_ipi(void) { }
static inline unsigned long wait_task_inactive(struct task_struct *p,
                           long match_state)
{
    return 1;
}
#endif

#define next_task(p) \
    list_entry_rcu((p)->tasks.next, struct task_struct, tasks)

#define for_each_process(p) \
    for (p = &init_task ; (p = next_task(p)) != &init_task ; )

extern bool current_is_single_threaded(void);

/*
 * Careful: do_each_thread/while_each_thread is a double loop so
 *          'break' will not work as expected - use goto instead.
 */
#define do_each_thread(g, t) \
    for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do

#define while_each_thread(g, t) \
    while ((t = next_thread(t)) != g)

#define __for_each_thread(signal, t)    \
    list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)

#define for_each_thread(p, t)       \
    __for_each_thread((p)->signal, t)

/* Careful: this is a double loop, 'break' won't work as expected. */
#define for_each_process_thread(p, t)   \
    for_each_process(p) for_each_thread(p, t)

static inline int get_nr_threads(struct task_struct *tsk)
{
    return tsk->signal->nr_threads;
}

static inline bool thread_group_leader(struct task_struct *p)
{
    return p->exit_signal >= 0;
}

/* Do to the insanities of de_thread it is possible for a process
 * to have the pid of the thread group leader without actually being
 * the thread group leader.  For iteration through the pids in proc
 * all we care about is that we have a task with the appropriate
 * pid, we don't actually care if we have the right task.
 */
static inline int has_group_leader_pid(struct task_struct *p)
{
    return p->pid == p->tgid;
}

static inline
int same_thread_group(struct task_struct *p1, struct task_struct *p2)
{
    return p1->tgid == p2->tgid;
}

static inline struct task_struct *next_thread(const struct task_struct *p)
{
    return list_entry_rcu(p->thread_group.next,
                  struct task_struct, thread_group);
}

static inline int thread_group_empty(struct task_struct *p)
{
    return list_empty(&p->thread_group);
}

#define delay_group_leader(p) \
        (thread_group_leader(p) && !thread_group_empty(p))

/*
 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
 * subscriptions and synchronises with wait4().  Also used in procfs.  Also
 * pins the final release of task.io_context.  Also protects ->cpuset and
 * ->cgroup.subsys[]. And ->vfork_done.
 *
 * Nests both inside and outside of read_lock(&tasklist_lock).
 * It must not be nested with write_lock_irq(&tasklist_lock),
 * neither inside nor outside.
 */
static inline void task_lock(struct task_struct *p)
{
    spin_lock(&p->alloc_lock);
}

static inline void task_unlock(struct task_struct *p)
{
    spin_unlock(&p->alloc_lock);
}

extern struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
                            unsigned long *flags);

static inline struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
                               unsigned long *flags)
{
    struct sighand_struct *ret;

    ret = __lock_task_sighand(tsk, flags);
    (void)__cond_lock(&tsk->sighand->siglock, ret);
    return ret;
}

static inline void unlock_task_sighand(struct task_struct *tsk,
                        unsigned long *flags)
{
    spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
}

#ifdef CONFIG_CGROUPS
static inline void threadgroup_change_begin(struct task_struct *tsk)
{
    down_read(&tsk->signal->group_rwsem);
}
static inline void threadgroup_change_end(struct task_struct *tsk)
{
    up_read(&tsk->signal->group_rwsem);
}

/**
 * threadgroup_lock - lock threadgroup
 * @tsk: member task of the threadgroup to lock
 *
 * Lock the threadgroup @tsk belongs to.  No new task is allowed to enter
 * and member tasks aren't allowed to exit (as indicated by PF_EXITING) or
 * change ->group_leader/pid.  This is useful for cases where the threadgroup
 * needs to stay stable across blockable operations.
 *
 * fork and exit paths explicitly call threadgroup_change_{begin|end}() for
 * synchronization.  While held, no new task will be added to threadgroup
 * and no existing live task will have its PF_EXITING set.
 *
 * de_thread() does threadgroup_change_{begin|end}() when a non-leader
 * sub-thread becomes a new leader.
 */
static inline void threadgroup_lock(struct task_struct *tsk)
{
    down_write(&tsk->signal->group_rwsem);
}

/**
 * threadgroup_unlock - unlock threadgroup
 * @tsk: member task of the threadgroup to unlock
 *
 * Reverse threadgroup_lock().
 */
static inline void threadgroup_unlock(struct task_struct *tsk)
{
    up_write(&tsk->signal->group_rwsem);
}
#else
static inline void threadgroup_change_begin(struct task_struct *tsk) {}
static inline void threadgroup_change_end(struct task_struct *tsk) {}
static inline void threadgroup_lock(struct task_struct *tsk) {}
static inline void threadgroup_unlock(struct task_struct *tsk) {}
#endif

#ifndef __HAVE_THREAD_FUNCTIONS

#define task_thread_info(task)  ((struct thread_info *)(task)->stack)
#define task_stack_page(task)   ((task)->stack)

static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)
{
    *task_thread_info(p) = *task_thread_info(org);
    task_thread_info(p)->task = p;
}

static inline unsigned long *end_of_stack(struct task_struct *p)
{
    return (unsigned long *)(task_thread_info(p) + 1);
}

#endif

static inline int object_is_on_stack(void *obj)
{
    void *stack = task_stack_page(current);

    return (obj >= stack) && (obj < (stack + THREAD_SIZE));
}

extern void thread_info_cache_init(void);

#ifdef CONFIG_DEBUG_STACK_USAGE
static inline unsigned long stack_not_used(struct task_struct *p)
{
    unsigned long *n = end_of_stack(p);

    do {    /* Skip over canary */
        n++;
    } while (!*n);

    return (unsigned long)n - (unsigned long)end_of_stack(p);
}
#endif

/* set thread flags in other task's structures
 * - see asm/thread_info.h for TIF_xxxx flags available
 */
static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
{
    set_ti_thread_flag(task_thread_info(tsk), flag);
}

static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
{
    clear_ti_thread_flag(task_thread_info(tsk), flag);
}

static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
{
    return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
}

static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
{
    return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
}

static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
{
    return test_ti_thread_flag(task_thread_info(tsk), flag);
}

static inline void set_tsk_need_resched(struct task_struct *tsk)
{
    set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
}

static inline void clear_tsk_need_resched(struct task_struct *tsk)
{
    clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
}

static inline int test_tsk_need_resched(struct task_struct *tsk)
{
    return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
}

static inline int restart_syscall(void)
{
    set_tsk_thread_flag(current, TIF_SIGPENDING);
    return -ERESTARTNOINTR;
}

static inline int signal_pending(struct task_struct *p)
{
    return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
}

static inline int __fatal_signal_pending(struct task_struct *p)
{
    return unlikely(sigismember(&p->pending.signal, SIGKILL));
}

static inline int fatal_signal_pending(struct task_struct *p)
{
    return signal_pending(p) && __fatal_signal_pending(p);
}

static inline int signal_pending_state(long state, struct task_struct *p)
{
    if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
        return 0;
    if (!signal_pending(p))
        return 0;

    return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
}

static inline int need_resched(void)
{
    return unlikely(test_thread_flag(TIF_NEED_RESCHED));
}

/*
 * cond_resched() and cond_resched_lock(): latency reduction via
 * explicit rescheduling in places that are safe. The return
 * value indicates whether a reschedule was done in fact.
 * cond_resched_lock() will drop the spinlock before scheduling,
 * cond_resched_softirq() will enable bhs before scheduling.
 */
extern int _cond_resched(void);

#define cond_resched() ({           \
    __might_sleep(__FILE__, __LINE__, 0);   \
    _cond_resched();            \
})

extern int __cond_resched_lock(spinlock_t *lock);

#ifdef CONFIG_PREEMPT_COUNT
#define PREEMPT_LOCK_OFFSET PREEMPT_OFFSET
#else
#define PREEMPT_LOCK_OFFSET 0
#endif

#define cond_resched_lock(lock) ({              \
    __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \
    __cond_resched_lock(lock);              \
})

extern int __cond_resched_softirq(void);

#define cond_resched_softirq() ({                   \
    __might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET);  \
    __cond_resched_softirq();                   \
})

/*
 * Does a critical section need to be broken due to another
 * task waiting?: (technically does not depend on CONFIG_PREEMPT,
 * but a general need for low latency)
 */
static inline int spin_needbreak(spinlock_t *lock)
{
#ifdef CONFIG_PREEMPT
    return spin_is_contended(lock);
#else
    return 0;
#endif
}

/*
 * Idle thread specific functions to determine the need_resched
 * polling state. We have two versions, one based on TS_POLLING in
 * thread_info.status and one based on TIF_POLLING_NRFLAG in
 * thread_info.flags
 */
#ifdef TS_POLLING
static inline int tsk_is_polling(struct task_struct *p)
{
    return task_thread_info(p)->status & TS_POLLING;
}
static inline void current_set_polling(void)
{
    current_thread_info()->status |= TS_POLLING;
}

static inline void current_clr_polling(void)
{
    current_thread_info()->status &= ~TS_POLLING;
    smp_mb__after_clear_bit();
}
#elif defined(TIF_POLLING_NRFLAG)
static inline int tsk_is_polling(struct task_struct *p)
{
    return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG);
}
static inline void current_set_polling(void)
{
    set_thread_flag(TIF_POLLING_NRFLAG);
}

static inline void current_clr_polling(void)
{
    clear_thread_flag(TIF_POLLING_NRFLAG);
}
#else
static inline int tsk_is_polling(struct task_struct *p) { return 0; }
static inline void current_set_polling(void) { }
static inline void current_clr_polling(void) { }
#endif

/*
 * Thread group CPU time accounting.
 */
void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times);

static inline void thread_group_cputime_init(struct signal_struct *sig)
{
    raw_spin_lock_init(&sig->cputimer.lock);
}

/*
 * Reevaluate whether the task has signals pending delivery.
 * Wake the task if so.
 * This is required every time the blocked sigset_t changes.
 * callers must hold sighand->siglock.
 */
extern void recalc_sigpending_and_wake(struct task_struct *t);
extern void recalc_sigpending(void);

extern void signal_wake_up_state(struct task_struct *t, unsigned int state);

static inline void signal_wake_up(struct task_struct *t, bool resume)
{
    signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
}
static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
{
    signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
}

/*
 * Wrappers for p->thread_info->cpu access. No-op on UP.
 */
#ifdef CONFIG_SMP

static inline unsigned int task_cpu(const struct task_struct *p)
{
    return task_thread_info(p)->cpu;
}

extern void set_task_cpu(struct task_struct *p, unsigned int cpu);

#else

static inline unsigned int task_cpu(const struct task_struct *p)
{
    return 0;
}

static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
{
}

#endif /* CONFIG_SMP */

extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
extern long sched_getaffinity(pid_t pid, struct cpumask *mask);

#ifdef CONFIG_CGROUP_SCHED
extern struct task_group root_task_group;
#endif /* CONFIG_CGROUP_SCHED */

extern int task_can_switch_user(struct user_struct *up,
                    struct task_struct *tsk);

#ifdef CONFIG_TASK_XACCT
static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
{
    tsk->ioac.rchar += amt;
}

static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
{
    tsk->ioac.wchar += amt;
}

static inline void inc_syscr(struct task_struct *tsk)
{
    tsk->ioac.syscr++;
}

static inline void inc_syscw(struct task_struct *tsk)
{
    tsk->ioac.syscw++;
}
#else
static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
{
}

static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
{
}

static inline void inc_syscr(struct task_struct *tsk)
{
}

static inline void inc_syscw(struct task_struct *tsk)
{
}
#endif

#ifndef TASK_SIZE_OF
#define TASK_SIZE_OF(tsk)   TASK_SIZE
#endif

#ifdef CONFIG_MM_OWNER
extern void mm_update_next_owner(struct mm_struct *mm);
extern void mm_init_owner(struct mm_struct *mm, struct task_struct *p);
#else
static inline void mm_update_next_owner(struct mm_struct *mm)
{
}

static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
{
}
#endif /* CONFIG_MM_OWNER */

static inline unsigned long task_rlimit(const struct task_struct *tsk,
        unsigned int limit)
{
    return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_cur);
}

static inline unsigned long task_rlimit_max(const struct task_struct *tsk,
        unsigned int limit)
{
    return ACCESS_ONCE(tsk->signal->rlim[limit].rlim_max);
}

static inline unsigned long rlimit(unsigned int limit)
{
    return task_rlimit(current, limit);
}

static inline unsigned long rlimit_max(unsigned int limit)
{
    return task_rlimit_max(current, limit);
}

#endif