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  • task_struct原码解读

    该结构体在linux中的路径为如下,如果是本地也可以根据以下子目录找到task_struct结构体,该结构体源码中在600多行

    https://github.com/torvalds/linux/blob/master/include/linux/sched.h

    如下解读:

    /* SPDX-License-Identifier: GPL-2.0 */
    #ifndef _LINUX_SCHED_H
    #define _LINUX_SCHED_H
    
    /*
     * Define 'struct task_struct' and provide the main scheduler
     * APIs (schedule(), wakeup variants, etc.)
     */
    
    #include <uapi/linux/sched.h>
    
    #include <asm/current.h>
    
    #include <linux/pid.h>
    #include <linux/sem.h>
    #include <linux/shm.h>
    #include <linux/kcov.h>
    #include <linux/mutex.h>
    #include <linux/plist.h>
    #include <linux/hrtimer.h>
    #include <linux/seccomp.h>
    #include <linux/nodemask.h>
    #include <linux/rcupdate.h>
    #include <linux/refcount.h>
    #include <linux/resource.h>
    #include <linux/latencytop.h>
    #include <linux/sched/prio.h>
    #include <linux/sched/types.h>
    #include <linux/signal_types.h>
    #include <linux/mm_types_task.h>
    #include <linux/task_io_accounting.h>
    #include <linux/posix-timers.h>
    #include <linux/rseq.h>
    
    /* task_struct member predeclarations (sorted alphabetically): */
    struct audit_context;
    struct backing_dev_info;
    struct bio_list;
    struct blk_plug;
    struct capture_control;
    struct cfs_rq;
    struct fs_struct;
    struct futex_pi_state;
    struct io_context;
    struct mempolicy;
    struct nameidata;
    struct nsproxy;
    struct perf_event_context;
    struct pid_namespace;
    struct pipe_inode_info;
    struct rcu_node;
    struct reclaim_state;
    struct robust_list_head;
    struct root_domain;
    struct rq;
    struct sched_attr;
    struct sched_param;
    struct seq_file;
    struct sighand_struct;
    struct signal_struct;
    struct task_delay_info;
    struct task_group;
    
    /*
     * 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.
     */
    
    /* Used in tsk->state: */
    #define TASK_RUNNING			0x0000
    #define TASK_INTERRUPTIBLE		0x0001
    #define TASK_UNINTERRUPTIBLE		0x0002
    #define __TASK_STOPPED			0x0004
    #define __TASK_TRACED			0x0008
    /* Used in tsk->exit_state: */
    #define EXIT_DEAD			0x0010
    #define EXIT_ZOMBIE			0x0020
    #define EXIT_TRACE			(EXIT_ZOMBIE | EXIT_DEAD)
    /* Used in tsk->state again: */
    #define TASK_PARKED			0x0040
    #define TASK_DEAD			0x0080
    #define TASK_WAKEKILL			0x0100
    #define TASK_WAKING			0x0200
    #define TASK_NOLOAD			0x0400
    #define TASK_NEW			0x0800
    #define TASK_STATE_MAX			0x1000
    
    /* Convenience macros for the sake of set_current_state: */
    #define TASK_KILLABLE			(TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
    #define TASK_STOPPED			(TASK_WAKEKILL | __TASK_STOPPED)
    #define TASK_TRACED			(TASK_WAKEKILL | __TASK_TRACED)
    
    #define TASK_IDLE			(TASK_UNINTERRUPTIBLE | TASK_NOLOAD)
    
    /* Convenience macros for the sake of wake_up(): */
    #define TASK_NORMAL			(TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
    
    /* get_task_state(): */
    #define TASK_REPORT			(TASK_RUNNING | TASK_INTERRUPTIBLE | 
    					 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | 
    					 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | 
    					 TASK_PARKED)
    
    #define task_is_traced(task)		((task->state & __TASK_TRACED) != 0)
    
    #define task_is_stopped(task)		((task->state & __TASK_STOPPED) != 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 && 
    					 (task->state & TASK_NOLOAD) == 0)
    
    #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
    
    /*
     * Special states are those that do not use the normal wait-loop pattern. See
     * the comment with set_special_state().
     */
    #define is_special_task_state(state)				
    	((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED | TASK_DEAD))
    
    #define __set_current_state(state_value)			
    	do {							
    		WARN_ON_ONCE(is_special_task_state(state_value));
    		current->task_state_change = _THIS_IP_;		
    		current->state = (state_value);			
    	} while (0)
    
    #define set_current_state(state_value)				
    	do {							
    		WARN_ON_ONCE(is_special_task_state(state_value));
    		current->task_state_change = _THIS_IP_;		
    		smp_store_mb(current->state, (state_value));	
    	} while (0)
    
    #define set_special_state(state_value)					
    	do {								
    		unsigned long flags; /* may shadow */			
    		WARN_ON_ONCE(!is_special_task_state(state_value));	
    		raw_spin_lock_irqsave(&current->pi_lock, flags);	
    		current->task_state_change = _THIS_IP_;			
    		current->state = (state_value);				
    		raw_spin_unlock_irqrestore(&current->pi_lock, flags);	
    	} while (0)
    #else
    /*
     * 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:
     *
     *   for (;;) {
     *	set_current_state(TASK_UNINTERRUPTIBLE);
     *	if (!need_sleep)
     *		break;
     *
     *	schedule();
     *   }
     *   __set_current_state(TASK_RUNNING);
     *
     * If the caller does not need such serialisation (because, for instance, the
     * condition test and condition change and wakeup are under the same lock) then
     * use __set_current_state().
     *
     * The above is typically ordered against the wakeup, which does:
     *
     *   need_sleep = false;
     *   wake_up_state(p, TASK_UNINTERRUPTIBLE);
     *
     * where wake_up_state() executes a full memory barrier before accessing the
     * task state.
     *
     * Wakeup will do: if (@state & p->state) p->state = TASK_RUNNING, that is,
     * once it observes the TASK_UNINTERRUPTIBLE store the waking CPU can issue a
     * TASK_RUNNING store which can collide with __set_current_state(TASK_RUNNING).
     *
     * However, with slightly different timing the wakeup TASK_RUNNING store can
     * also collide with the TASK_UNINTERRUPTIBLE store. Losing that store is not
     * a problem either because that will result in one extra go around the loop
     * and our @cond test will save the day.
     *
     * Also see the comments of try_to_wake_up().
     */
    #define __set_current_state(state_value)				
    	current->state = (state_value)
    
    #define set_current_state(state_value)					
    	smp_store_mb(current->state, (state_value))
    
    /*
     * set_special_state() should be used for those states when the blocking task
     * can not use the regular condition based wait-loop. In that case we must
     * serialize against wakeups such that any possible in-flight TASK_RUNNING stores
     * will not collide with our state change.
     */
    #define set_special_state(state_value)					
    	do {								
    		unsigned long flags; /* may shadow */			
    		raw_spin_lock_irqsave(&current->pi_lock, flags);	
    		current->state = (state_value);				
    		raw_spin_unlock_irqrestore(&current->pi_lock, flags);	
    	} while (0)
    
    #endif
    
    /* Task command name length: */
    #define TASK_COMM_LEN			16
    
    extern void scheduler_tick(void);
    
    #define	MAX_SCHEDULE_TIMEOUT		LONG_MAX
    
    extern long schedule_timeout(long timeout);
    extern long schedule_timeout_interruptible(long timeout);
    extern long schedule_timeout_killable(long timeout);
    extern long schedule_timeout_uninterruptible(long timeout);
    extern long schedule_timeout_idle(long timeout);
    asmlinkage void schedule(void);
    extern void schedule_preempt_disabled(void);
    asmlinkage void preempt_schedule_irq(void);
    
    extern int __must_check io_schedule_prepare(void);
    extern void io_schedule_finish(int token);
    extern long io_schedule_timeout(long timeout);
    extern void io_schedule(void);
    
    /**
     * struct prev_cputime - snapshot of system and user cputime
     * @utime: time spent in user mode
     * @stime: time spent in system mode
     * @lock: protects the above two fields
     *
     * Stores previous user/system time values such that we can guarantee
     * monotonicity.
     */
    struct prev_cputime {
    #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
    	u64				utime;
    	u64				stime;
    	raw_spinlock_t			lock;
    #endif
    };
    
    enum vtime_state {
    	/* Task is sleeping or running in a CPU with VTIME inactive: */
    	VTIME_INACTIVE = 0,
    	/* Task is idle */
    	VTIME_IDLE,
    	/* Task runs in kernelspace in a CPU with VTIME active: */
    	VTIME_SYS,
    	/* Task runs in userspace in a CPU with VTIME active: */
    	VTIME_USER,
    	/* Task runs as guests in a CPU with VTIME active: */
    	VTIME_GUEST,
    };
    
    struct vtime {
    	seqcount_t		seqcount;
    	unsigned long long	starttime;
    	enum vtime_state	state;
    	unsigned int		cpu;
    	u64			utime;
    	u64			stime;
    	u64			gtime;
    };
    
    /*
     * Utilization clamp constraints.
     * @UCLAMP_MIN:	Minimum utilization
     * @UCLAMP_MAX:	Maximum utilization
     * @UCLAMP_CNT:	Utilization clamp constraints count
     */
    enum uclamp_id {
    	UCLAMP_MIN = 0,
    	UCLAMP_MAX,
    	UCLAMP_CNT
    };
    
    #ifdef CONFIG_SMP
    extern struct root_domain def_root_domain;
    extern struct mutex sched_domains_mutex;
    #endif
    
    struct sched_info {
    #ifdef CONFIG_SCHED_INFO
    	/* Cumulative counters: */
    
    	/* # of times we have run on this CPU: */
    	unsigned long			pcount;
    
    	/* Time spent waiting on a runqueue: */
    	unsigned long long		run_delay;
    
    	/* Timestamps: */
    
    	/* When did we last run on a CPU? */
    	unsigned long long		last_arrival;
    
    	/* When were we last queued to run? */
    	unsigned long long		last_queued;
    
    #endif /* CONFIG_SCHED_INFO */
    };
    
    /*
     * Integer metrics need fixed point arithmetic, e.g., sched/fair
     * has a few: load, load_avg, util_avg, freq, and capacity.
     *
     * We define a basic fixed point arithmetic range, and then formalize
     * all these metrics based on that basic range.
     */
    # define SCHED_FIXEDPOINT_SHIFT		10
    # define SCHED_FIXEDPOINT_SCALE		(1L << SCHED_FIXEDPOINT_SHIFT)
    
    /* Increase resolution of cpu_capacity calculations */
    # define SCHED_CAPACITY_SHIFT		SCHED_FIXEDPOINT_SHIFT
    # define SCHED_CAPACITY_SCALE		(1L << SCHED_CAPACITY_SHIFT)
    
    struct load_weight {
    	unsigned long			weight;
    	u32				inv_weight;
    };
    
    /**
     * struct util_est - Estimation utilization of FAIR tasks
     * @enqueued: instantaneous estimated utilization of a task/cpu
     * @ewma:     the Exponential Weighted Moving Average (EWMA)
     *            utilization of a task
     *
     * Support data structure to track an Exponential Weighted Moving Average
     * (EWMA) of a FAIR task's utilization. New samples are added to the moving
     * average each time a task completes an activation. Sample's weight is chosen
     * so that the EWMA will be relatively insensitive to transient changes to the
     * task's workload.
     *
     * The enqueued attribute has a slightly different meaning for tasks and cpus:
     * - task:   the task's util_avg at last task dequeue time
     * - cfs_rq: the sum of util_est.enqueued for each RUNNABLE task on that CPU
     * Thus, the util_est.enqueued of a task represents the contribution on the
     * estimated utilization of the CPU where that task is currently enqueued.
     *
     * Only for tasks we track a moving average of the past instantaneous
     * estimated utilization. This allows to absorb sporadic drops in utilization
     * of an otherwise almost periodic task.
     */
    struct util_est {
    	unsigned int			enqueued;
    	unsigned int			ewma;
    #define UTIL_EST_WEIGHT_SHIFT		2
    } __attribute__((__aligned__(sizeof(u64))));
    
    /*
     * The load_avg/util_avg accumulates an infinite geometric series
     * (see __update_load_avg() in kernel/sched/fair.c).
     *
     * [load_avg definition]
     *
     *   load_avg = runnable% * scale_load_down(load)
     *
     * where runnable% is the time ratio that a sched_entity is runnable.
     * For cfs_rq, it is the aggregated load_avg of all runnable and
     * blocked sched_entities.
     *
     * [util_avg definition]
     *
     *   util_avg = running% * SCHED_CAPACITY_SCALE
     *
     * where running% is the time ratio that a sched_entity is running on
     * a CPU. For cfs_rq, it is the aggregated util_avg of all runnable
     * and blocked sched_entities.
     *
     * load_avg and util_avg don't direcly factor frequency scaling and CPU
     * capacity scaling. The scaling is done through the rq_clock_pelt that
     * is used for computing those signals (see update_rq_clock_pelt())
     *
     * N.B., the above ratios (runnable% and running%) themselves are in the
     * range of [0, 1]. To do fixed point arithmetics, we therefore scale them
     * to as large a range as necessary. This is for example reflected by
     * util_avg's SCHED_CAPACITY_SCALE.
     *
     * [Overflow issue]
     *
     * The 64-bit load_sum can have 4353082796 (=2^64/47742/88761) entities
     * with the highest load (=88761), always runnable on a single cfs_rq,
     * and should not overflow as the number already hits PID_MAX_LIMIT.
     *
     * For all other cases (including 32-bit kernels), struct load_weight's
     * weight will overflow first before we do, because:
     *
     *    Max(load_avg) <= Max(load.weight)
     *
     * Then it is the load_weight's responsibility to consider overflow
     * issues.
     */
    struct sched_avg {
    	u64				last_update_time;
    	u64				load_sum;
    	u64				runnable_load_sum;
    	u32				util_sum;
    	u32				period_contrib;
    	unsigned long			load_avg;
    	unsigned long			runnable_load_avg;
    	unsigned long			util_avg;
    	struct util_est			util_est;
    } ____cacheline_aligned;
    
    struct sched_statistics {
    #ifdef CONFIG_SCHEDSTATS
    	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 {
    	/* For load-balancing: */
    	struct load_weight		load;
    	unsigned long			runnable_weight;
    	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;
    
    	struct sched_statistics		statistics;
    
    #ifdef CONFIG_FAIR_GROUP_SCHED
    	int				depth;
    	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
    
    #ifdef CONFIG_SMP
    	/*
    	 * Per entity load average tracking.
    	 *
    	 * Put into separate cache line so it does not
    	 * collide with read-mostly values above.
    	 */
    	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;
    	unsigned short			on_rq;
    	unsigned short			on_list;
    
    	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
    } __randomize_layout;
    
    struct sched_dl_entity {
    	struct rb_node			rb_node;
    
    	/*
    	 * Original scheduling parameters. Copied here from sched_attr
    	 * during sched_setattr(), they will remain the same until
    	 * the next sched_setattr().
    	 */
    	u64				dl_runtime;	/* Maximum runtime for each instance	*/
    	u64				dl_deadline;	/* Relative deadline of each instance	*/
    	u64				dl_period;	/* Separation of two instances (period) */
    	u64				dl_bw;		/* dl_runtime / dl_period		*/
    	u64				dl_density;	/* dl_runtime / dl_deadline		*/
    
    	/*
    	 * Actual scheduling parameters. Initialized with the values above,
    	 * they are continuously updated during task execution. Note that
    	 * the remaining runtime could be < 0 in case we are in overrun.
    	 */
    	s64				runtime;	/* Remaining runtime for this instance	*/
    	u64				deadline;	/* Absolute deadline for this instance	*/
    	unsigned int			flags;		/* Specifying the scheduler behaviour	*/
    
    	/*
    	 * Some bool flags:
    	 *
    	 * @dl_throttled tells if we exhausted the runtime. If so, the
    	 * task has to wait for a replenishment to be performed at the
    	 * next firing of dl_timer.
    	 *
    	 * @dl_boosted tells if we are boosted due to DI. If so we are
    	 * outside bandwidth enforcement mechanism (but only until we
    	 * exit the critical section);
    	 *
    	 * @dl_yielded tells if task gave up the CPU before consuming
    	 * all its available runtime during the last job.
    	 *
    	 * @dl_non_contending tells if the task is inactive while still
    	 * contributing to the active utilization. In other words, it
    	 * indicates if the inactive timer has been armed and its handler
    	 * has not been executed yet. This flag is useful to avoid race
    	 * conditions between the inactive timer handler and the wakeup
    	 * code.
    	 *
    	 * @dl_overrun tells if the task asked to be informed about runtime
    	 * overruns.
    	 */
    	unsigned int			dl_throttled      : 1;
    	unsigned int			dl_boosted        : 1;
    	unsigned int			dl_yielded        : 1;
    	unsigned int			dl_non_contending : 1;
    	unsigned int			dl_overrun	  : 1;
    
    	/*
    	 * Bandwidth enforcement timer. Each -deadline task has its
    	 * own bandwidth to be enforced, thus we need one timer per task.
    	 */
    	struct hrtimer			dl_timer;
    
    	/*
    	 * Inactive timer, responsible for decreasing the active utilization
    	 * at the "0-lag time". When a -deadline task blocks, it contributes
    	 * to GRUB's active utilization until the "0-lag time", hence a
    	 * timer is needed to decrease the active utilization at the correct
    	 * time.
    	 */
    	struct hrtimer inactive_timer;
    };
    
    #ifdef CONFIG_UCLAMP_TASK
    /* Number of utilization clamp buckets (shorter alias) */
    #define UCLAMP_BUCKETS CONFIG_UCLAMP_BUCKETS_COUNT
    
    /*
     * Utilization clamp for a scheduling entity
     * @value:		clamp value "assigned" to a se
     * @bucket_id:		bucket index corresponding to the "assigned" value
     * @active:		the se is currently refcounted in a rq's bucket
     * @user_defined:	the requested clamp value comes from user-space
     *
     * The bucket_id is the index of the clamp bucket matching the clamp value
     * which is pre-computed and stored to avoid expensive integer divisions from
     * the fast path.
     *
     * The active bit is set whenever a task has got an "effective" value assigned,
     * which can be different from the clamp value "requested" from user-space.
     * This allows to know a task is refcounted in the rq's bucket corresponding
     * to the "effective" bucket_id.
     *
     * The user_defined bit is set whenever a task has got a task-specific clamp
     * value requested from userspace, i.e. the system defaults apply to this task
     * just as a restriction. This allows to relax default clamps when a less
     * restrictive task-specific value has been requested, thus allowing to
     * implement a "nice" semantic. For example, a task running with a 20%
     * default boost can still drop its own boosting to 0%.
     */
    struct uclamp_se {
    	unsigned int value		: bits_per(SCHED_CAPACITY_SCALE);
    	unsigned int bucket_id		: bits_per(UCLAMP_BUCKETS);
    	unsigned int active		: 1;
    	unsigned int user_defined	: 1;
    };
    #endif /* CONFIG_UCLAMP_TASK */
    
    union rcu_special {
    	struct {
    		u8			blocked;
    		u8			need_qs;
    		u8			exp_hint; /* Hint for performance. */
    		u8			deferred_qs;
    	} b; /* Bits. */
    	u32 s; /* Set of bits. */
    };
    
    enum perf_event_task_context {
    	perf_invalid_context = -1,
    	perf_hw_context = 0,
    	perf_sw_context,
    	perf_nr_task_contexts,
    };
    
    struct wake_q_node {
    	struct wake_q_node *next;
    };
    
    struct task_struct {
    #ifdef CONFIG_THREAD_INFO_IN_TASK
    	/*
    	 * For reasons of header soup (see current_thread_info()), this
    	 * must be the first element of task_struct.
    	 */
    	struct thread_info		thread_info;
    #endif
    	/* -1 unrunnable, 0 runnable, >0 stopped: */
    	volatile long			state;
    
    	/*
    	 * This begins the randomizable portion of task_struct. Only
    	 * scheduling-critical items should be added above here.
    	 */
    	randomized_struct_fields_start
    
    	void				*stack;
    	refcount_t			usage;
    	/* Per task flags (PF_*), defined further below: */
    	unsigned int			flags;
    	unsigned int			ptrace;
    
    #ifdef CONFIG_SMP
    	struct llist_node		wake_entry;
    	int				on_cpu;
    #ifdef CONFIG_THREAD_INFO_IN_TASK
    	/* Current CPU: */
    	unsigned int			cpu;
    #endif
    	unsigned int			wakee_flips;
    	unsigned long			wakee_flip_decay_ts;
    	struct task_struct		*last_wakee;
    
    	/*
    	 * recent_used_cpu is initially set as the last CPU used by a task
    	 * that wakes affine another task. Waker/wakee relationships can
    	 * push tasks around a CPU where each wakeup moves to the next one.
    	 * Tracking a recently used CPU allows a quick search for a recently
    	 * used CPU that may be idle.
    	 */
    	int				recent_used_cpu;
    	int				wake_cpu;
    #endif
    	int				on_rq;
    
    	int				prio;
    	int				static_prio;
    	int				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
    	struct sched_dl_entity		dl;
    
    #ifdef CONFIG_UCLAMP_TASK
    	/* Clamp values requested for a scheduling entity */
    	struct uclamp_se		uclamp_req[UCLAMP_CNT];
    	/* Effective clamp values used for a scheduling entity */
    	struct uclamp_se		uclamp[UCLAMP_CNT];
    #endif
    
    #ifdef CONFIG_PREEMPT_NOTIFIERS
    	/* List of struct preempt_notifier: */
    	struct hlist_head		preempt_notifiers;
    #endif
    
    #ifdef CONFIG_BLK_DEV_IO_TRACE
    	unsigned int			btrace_seq;
    #endif
    
    	unsigned int			policy;
    	int				nr_cpus_allowed;
    	const cpumask_t			*cpus_ptr;
    	cpumask_t			cpus_mask;
    
    #ifdef CONFIG_PREEMPT_RCU
    	int				rcu_read_lock_nesting;
    	union rcu_special		rcu_read_unlock_special;
    	struct list_head		rcu_node_entry;
    	struct rcu_node			*rcu_blocked_node;
    #endif /* #ifdef CONFIG_PREEMPT_RCU */
    
    #ifdef CONFIG_TASKS_RCU
    	unsigned long			rcu_tasks_nvcsw;
    	u8				rcu_tasks_holdout;
    	u8				rcu_tasks_idx;
    	int				rcu_tasks_idle_cpu;
    	struct list_head		rcu_tasks_holdout_list;
    #endif /* #ifdef CONFIG_TASKS_RCU */
    
    	struct sched_info		sched_info;
    
    	struct list_head		tasks;
    #ifdef CONFIG_SMP
    	struct plist_node		pushable_tasks;
    	struct rb_node			pushable_dl_tasks;
    #endif
    
    	struct mm_struct		*mm;
    	struct mm_struct		*active_mm;
    
    	/* Per-thread vma caching: */
    	struct vmacache			vmacache;
    
    #ifdef SPLIT_RSS_COUNTING
    	struct task_rss_stat		rss_stat;
    #endif
    	int				exit_state;
    	int				exit_code;
    	int				exit_signal;
    	/* The signal sent when the parent dies: */
    	int				pdeath_signal;
    	/* JOBCTL_*, siglock protected: */
    	unsigned long			jobctl;
    
    	/* Used for emulating ABI behavior of previous Linux versions: */
    	unsigned int			personality;
    
    	/* Scheduler bits, serialized by scheduler locks: */
    	unsigned			sched_reset_on_fork:1;
    	unsigned			sched_contributes_to_load:1;
    	unsigned			sched_migrated:1;
    	unsigned			sched_remote_wakeup:1;
    #ifdef CONFIG_PSI
    	unsigned			sched_psi_wake_requeue:1;
    #endif
    
    	/* Force alignment to the next boundary: */
    	unsigned			:0;
    
    	/* Unserialized, strictly 'current' */
    
    	/* Bit to tell LSMs we're in execve(): */
    	unsigned			in_execve:1;
    	unsigned			in_iowait:1;
    #ifndef TIF_RESTORE_SIGMASK
    	unsigned			restore_sigmask:1;
    #endif
    #ifdef CONFIG_MEMCG
    	unsigned			in_user_fault:1;
    #endif
    #ifdef CONFIG_COMPAT_BRK
    	unsigned			brk_randomized:1;
    #endif
    #ifdef CONFIG_CGROUPS
    	/* disallow userland-initiated cgroup migration */
    	unsigned			no_cgroup_migration:1;
    	/* task is frozen/stopped (used by the cgroup freezer) */
    	unsigned			frozen:1;
    #endif
    #ifdef CONFIG_BLK_CGROUP
    	/* to be used once the psi infrastructure lands upstream. */
    	unsigned			use_memdelay:1;
    #endif
    
    	unsigned long			atomic_flags; /* Flags requiring atomic access. */
    
    	struct restart_block		restart_block;
    
    	pid_t				pid;
    	pid_t				tgid;
    
    #ifdef CONFIG_STACKPROTECTOR
    	/* Canary value for the -fstack-protector GCC feature: */
    	unsigned long			stack_canary;
    #endif
    	/*
    	 * Pointers to the (original) parent process, youngest child, younger sibling,
    	 * older sibling, respectively.  (p->father can be replaced with
    	 * p->real_parent->pid)
    	 */
    
    	/* Real parent process: */
    	struct task_struct __rcu	*real_parent;
    
    	/* Recipient of SIGCHLD, wait4() reports: */
    	struct task_struct __rcu	*parent;
    
    	/*
    	 * Children/sibling form the list of natural children:
    	 */
    	struct list_head		children;
    	struct list_head		sibling;
    	struct task_struct		*group_leader;
    
    	/*
    	 * 'ptraced' is the list of tasks this task is using ptrace() on.
    	 *
    	 * This includes both natural children and PTRACE_ATTACH targets.
    	 * 'ptrace_entry' is this task's link on the p->parent->ptraced list.
    	 */
    	struct list_head		ptraced;
    	struct list_head		ptrace_entry;
    
    	/* PID/PID hash table linkage. */
    	struct pid			*thread_pid;
    	struct hlist_node		pid_links[PIDTYPE_MAX];
    	struct list_head		thread_group;
    	struct list_head		thread_node;
    
    	struct completion		*vfork_done;
    
    	/* CLONE_CHILD_SETTID: */
    	int __user			*set_child_tid;
    
    	/* CLONE_CHILD_CLEARTID: */
    	int __user			*clear_child_tid;
    
    	u64				utime;
    	u64				stime;
    #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
    	u64				utimescaled;
    	u64				stimescaled;
    #endif
    	u64				gtime;
    	struct prev_cputime		prev_cputime;
    #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
    	struct vtime			vtime;
    #endif
    
    #ifdef CONFIG_NO_HZ_FULL
    	atomic_t			tick_dep_mask;
    #endif
    	/* Context switch counts: */
    	unsigned long			nvcsw;
    	unsigned long			nivcsw;
    
    	/* Monotonic time in nsecs: */
    	u64				start_time;
    
    	/* Boot based time in nsecs: */
    	u64				start_boottime;
    
    	/* MM fault and swap info: this can arguably be seen as either mm-specific or thread-specific: */
    	unsigned long			min_flt;
    	unsigned long			maj_flt;
    
    	/* Empty if CONFIG_POSIX_CPUTIMERS=n */
    	struct posix_cputimers		posix_cputimers;
    
    	/* Process credentials: */
    
    	/* Tracer's credentials at attach: */
    	const struct cred __rcu		*ptracer_cred;
    
    	/* Objective and real subjective task credentials (COW): */
    	const struct cred __rcu		*real_cred;
    
    	/* Effective (overridable) subjective task credentials (COW): */
    	const struct cred __rcu		*cred;
    
    #ifdef CONFIG_KEYS
    	/* Cached requested key. */
    	struct key			*cached_requested_key;
    #endif
    
    	/*
    	 * executable name, excluding path.
    	 *
    	 * - normally initialized setup_new_exec()
    	 * - access it with [gs]et_task_comm()
    	 * - lock it with task_lock()
    	 */
    	char				comm[TASK_COMM_LEN];
    
    	struct nameidata		*nameidata;
    
    #ifdef CONFIG_SYSVIPC
    	struct sysv_sem			sysvsem;
    	struct sysv_shm			sysvshm;
    #endif
    #ifdef CONFIG_DETECT_HUNG_TASK
    	unsigned long			last_switch_count;
    	unsigned long			last_switch_time;
    #endif
    	/* 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;
    	sigset_t			real_blocked;
    	/* Restored if set_restore_sigmask() was used: */
    	sigset_t			saved_sigmask;
    	struct sigpending		pending;
    	unsigned long			sas_ss_sp;
    	size_t				sas_ss_size;
    	unsigned int			sas_ss_flags;
    
    	struct callback_head		*task_works;
    
    #ifdef CONFIG_AUDIT
    #ifdef CONFIG_AUDITSYSCALL
    	struct audit_context		*audit_context;
    #endif
    	kuid_t				loginuid;
    	unsigned int			sessionid;
    #endif
    	struct seccomp			seccomp;
    
    	/* Thread group tracking: */
    	u32				parent_exec_id;
    	u32				self_exec_id;
    
    	/* Protection against (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;
    
    	struct wake_q_node		wake_q;
    
    #ifdef CONFIG_RT_MUTEXES
    	/* PI waiters blocked on a rt_mutex held by this task: */
    	struct rb_root_cached		pi_waiters;
    	/* Updated under owner's pi_lock and rq lock */
    	struct task_struct		*pi_top_task;
    	/* 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_DEBUG_ATOMIC_SLEEP
    	int				non_block_count;
    #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];
    #endif
    
    #ifdef CONFIG_UBSAN
    	unsigned int			in_ubsan;
    #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;
    
    #ifdef CONFIG_COMPACTION
    	struct capture_control		*capture_control;
    #endif
    	/* Ptrace state: */
    	unsigned long			ptrace_message;
    	kernel_siginfo_t		*last_siginfo;
    
    	struct task_io_accounting	ioac;
    #ifdef CONFIG_PSI
    	/* Pressure stall state */
    	unsigned int			psi_flags;
    #endif
    #ifdef CONFIG_TASK_XACCT
    	/* Accumulated RSS usage: */
    	u64				acct_rss_mem1;
    	/* Accumulated virtual memory usage: */
    	u64				acct_vm_mem1;
    	/* stime + utime since last update: */
    	u64				acct_timexpd;
    #endif
    #ifdef CONFIG_CPUSETS
    	/* Protected by ->alloc_lock: */
    	nodemask_t			mems_allowed;
    	/* Seqence number to catch updates: */
    	seqcount_t			mems_allowed_seq;
    	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_X86_CPU_RESCTRL
    	u32				closid;
    	u32				rmid;
    #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;
    	struct mutex			futex_exit_mutex;
    	unsigned int			futex_state;
    #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_DEBUG_PREEMPT
    	unsigned long			preempt_disable_ip;
    #endif
    #ifdef CONFIG_NUMA
    	/* Protected by alloc_lock: */
    	struct mempolicy		*mempolicy;
    	short				il_prev;
    	short				pref_node_fork;
    #endif
    #ifdef CONFIG_NUMA_BALANCING
    	int				numa_scan_seq;
    	unsigned int			numa_scan_period;
    	unsigned int			numa_scan_period_max;
    	int				numa_preferred_nid;
    	unsigned long			numa_migrate_retry;
    	/* Migration stamp: */
    	u64				node_stamp;
    	u64				last_task_numa_placement;
    	u64				last_sum_exec_runtime;
    	struct callback_head		numa_work;
    
    	/*
    	 * This pointer is only modified for current in syscall and
    	 * pagefault context (and for tasks being destroyed), so it can be read
    	 * from any of the following contexts:
    	 *  - RCU read-side critical section
    	 *  - current->numa_group from everywhere
    	 *  - task's runqueue locked, task not running
    	 */
    	struct numa_group __rcu		*numa_group;
    
    	/*
    	 * numa_faults is an array split into four regions:
    	 * faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
    	 * in this precise order.
    	 *
    	 * faults_memory: Exponential decaying average of faults on a per-node
    	 * basis. Scheduling placement decisions are made based on these
    	 * counts. The values remain static for the duration of a PTE scan.
    	 * faults_cpu: Track the nodes the process was running on when a NUMA
    	 * hinting fault was incurred.
    	 * faults_memory_buffer and faults_cpu_buffer: Record faults per node
    	 * during the current scan window. When the scan completes, the counts
    	 * in faults_memory and faults_cpu decay and these values are copied.
    	 */
    	unsigned long			*numa_faults;
    	unsigned long			total_numa_faults;
    
    	/*
    	 * numa_faults_locality tracks if faults recorded during the last
    	 * scan window were remote/local or failed to migrate. The task scan
    	 * period is adapted based on the locality of the faults with different
    	 * weights depending on whether they were shared or private faults
    	 */
    	unsigned long			numa_faults_locality[3];
    
    	unsigned long			numa_pages_migrated;
    #endif /* CONFIG_NUMA_BALANCING */
    
    #ifdef CONFIG_RSEQ
    	struct rseq __user *rseq;
    	u32 rseq_sig;
    	/*
    	 * RmW on rseq_event_mask must be performed atomically
    	 * with respect to preemption.
    	 */
    	unsigned long rseq_event_mask;
    #endif
    
    	struct tlbflush_unmap_batch	tlb_ubc;
    
    	union {
    		refcount_t		rcu_users;
    		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;
    	unsigned int			fail_nth;
    #endif
    	/*
    	 * When (nr_dirtied >= nr_dirtied_pause), it's time to call
    	 * balance_dirty_pages() for a dirty throttling pause:
    	 */
    	int				nr_dirtied;
    	int				nr_dirtied_pause;
    	/* Start of a write-and-pause period: */
    	unsigned long			dirty_paused_when;
    
    #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.
    	 */
    	u64				timer_slack_ns;
    	u64				default_timer_slack_ns;
    
    #ifdef CONFIG_KASAN
    	unsigned int			kasan_depth;
    #endif
    
    #ifdef CONFIG_FUNCTION_GRAPH_TRACER
    	/* Index of current stored address in ret_stack: */
    	int				curr_ret_stack;
    	int				curr_ret_depth;
    
    	/* Stack of return addresses for return function tracing: */
    	struct ftrace_ret_stack		*ret_stack;
    
    	/* Timestamp 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 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_KCOV
    	/* See kernel/kcov.c for more details. */
    
    	/* Coverage collection mode enabled for this task (0 if disabled): */
    	unsigned int			kcov_mode;
    
    	/* Size of the kcov_area: */
    	unsigned int			kcov_size;
    
    	/* Buffer for coverage collection: */
    	void				*kcov_area;
    
    	/* KCOV descriptor wired with this task or NULL: */
    	struct kcov			*kcov;
    
    	/* KCOV common handle for remote coverage collection: */
    	u64				kcov_handle;
    
    	/* KCOV sequence number: */
    	int				kcov_sequence;
    #endif
    
    #ifdef CONFIG_MEMCG
    	struct mem_cgroup		*memcg_in_oom;
    	gfp_t				memcg_oom_gfp_mask;
    	int				memcg_oom_order;
    
    	/* Number of pages to reclaim on returning to userland: */
    	unsigned int			memcg_nr_pages_over_high;
    
    	/* Used by memcontrol for targeted memcg charge: */
    	struct mem_cgroup		*active_memcg;
    #endif
    
    #ifdef CONFIG_BLK_CGROUP
    	struct request_queue		*throttle_queue;
    #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
    #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
    	unsigned long			task_state_change;
    #endif
    	int				pagefault_disabled;
    #ifdef CONFIG_MMU
    	struct task_struct		*oom_reaper_list;
    #endif
    #ifdef CONFIG_VMAP_STACK
    	struct vm_struct		*stack_vm_area;
    #endif
    #ifdef CONFIG_THREAD_INFO_IN_TASK
    	/* A live task holds one reference: */
    	refcount_t			stack_refcount;
    #endif
    #ifdef CONFIG_LIVEPATCH
    	int patch_state;
    #endif
    #ifdef CONFIG_SECURITY
    	/* Used by LSM modules for access restriction: */
    	void				*security;
    #endif
    
    #ifdef CONFIG_GCC_PLUGIN_STACKLEAK
    	unsigned long			lowest_stack;
    	unsigned long			prev_lowest_stack;
    #endif
    
    	/*
    	 * New fields for task_struct should be added above here, so that
    	 * they are included in the randomized portion of task_struct.
    	 */
    	randomized_struct_fields_end
    
    	/* CPU-specific state of this task: */
    	struct thread_struct		thread;
    
    	/*
    	 * WARNING: on x86, 'thread_struct' contains a variable-sized
    	 * structure.  It *MUST* be at the end of 'task_struct'.
    	 *
    	 * Do not put anything below here!
    	 */
    };
    
    static inline struct pid *task_pid(struct task_struct *task)
    {
    	return task->thread_pid;
    }
    
    /*
     * 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;
     *
     * 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_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.
     *
     * Return: 1 if the process is alive. 0 otherwise.
     */
    static inline int pid_alive(const struct task_struct *p)
    {
    	return p->thread_pid != NULL;
    }
    
    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);
    }
    
    static inline pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
    {
    	return __task_pid_nr_ns(tsk, PIDTYPE_TGID, ns);
    }
    
    static inline pid_t task_tgid_vnr(struct task_struct *tsk)
    {
    	return __task_pid_nr_ns(tsk, PIDTYPE_TGID, NULL);
    }
    
    static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns)
    {
    	pid_t pid = 0;
    
    	rcu_read_lock();
    	if (pid_alive(tsk))
    		pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns);
    	rcu_read_unlock();
    
    	return pid;
    }
    
    static inline pid_t task_ppid_nr(const struct task_struct *tsk)
    {
    	return task_ppid_nr_ns(tsk, &init_pid_ns);
    }
    
    /* Obsolete, do not use: */
    static inline pid_t task_pgrp_nr(struct task_struct *tsk)
    {
    	return task_pgrp_nr_ns(tsk, &init_pid_ns);
    }
    
    #define TASK_REPORT_IDLE	(TASK_REPORT + 1)
    #define TASK_REPORT_MAX		(TASK_REPORT_IDLE << 1)
    
    static inline unsigned int task_state_index(struct task_struct *tsk)
    {
    	unsigned int tsk_state = READ_ONCE(tsk->state);
    	unsigned int state = (tsk_state | tsk->exit_state) & TASK_REPORT;
    
    	BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX);
    
    	if (tsk_state == TASK_IDLE)
    		state = TASK_REPORT_IDLE;
    
    	return fls(state);
    }
    
    static inline char task_index_to_char(unsigned int state)
    {
    	static const char state_char[] = "RSDTtXZPI";
    
    	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != sizeof(state_char) - 1);
    
    	return state_char[state];
    }
    
    static inline char task_state_to_char(struct task_struct *tsk)
    {
    	return task_index_to_char(task_state_index(tsk));
    }
    
    /**
     * is_global_init - check if a task structure is init. Since init
     * is free to have sub-threads we need to check tgid.
     * @tsk: Task structure to be checked.
     *
     * Check if a task structure is the first user space task the kernel created.
     *
     * Return: 1 if the task structure is init. 0 otherwise.
     */
    static inline int is_global_init(struct task_struct *tsk)
    {
    	return task_tgid_nr(tsk) == 1;
    }
    
    extern struct pid *cad_pid;
    
    /*
     * Per process flags
     */
    #define PF_IDLE			0x00000002	/* I am an IDLE thread */
    #define PF_EXITING		0x00000004	/* Getting 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_KSWAPD		0x00020000	/* I am kswapd */
    #define PF_MEMALLOC_NOFS	0x00040000	/* All allocation requests will inherit GFP_NOFS */
    #define PF_MEMALLOC_NOIO	0x00080000	/* All allocation requests will inherit GFP_NOIO */
    #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_MEMSTALL		0x01000000	/* Stalled due to lack of memory */
    #define PF_UMH			0x02000000	/* I'm an Usermodehelper process */
    #define PF_NO_SETAFFINITY	0x04000000	/* Userland is not allowed to meddle with cpus_mask */
    #define PF_MCE_EARLY		0x08000000      /* Early kill for mce process policy */
    #define PF_MEMALLOC_NOCMA	0x10000000	/* All allocation request will have _GFP_MOVABLE cleared */
    #define PF_IO_WORKER		0x20000000	/* Task is an IO worker */
    #define PF_FREEZER_SKIP		0x40000000	/* Freezer should not count it as freezable */
    #define PF_SUSPEND_TASK		0x80000000      /* This thread called freeze_processes() and should not be frozen */
    
    /*
     * 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)
    
    static inline bool is_percpu_thread(void)
    {
    #ifdef CONFIG_SMP
    	return (current->flags & PF_NO_SETAFFINITY) &&
    		(current->nr_cpus_allowed  == 1);
    #else
    	return true;
    #endif
    }
    
    /* Per-process atomic flags. */
    #define PFA_NO_NEW_PRIVS		0	/* May not gain new privileges. */
    #define PFA_SPREAD_PAGE			1	/* Spread page cache over cpuset */
    #define PFA_SPREAD_SLAB			2	/* Spread some slab caches over cpuset */
    #define PFA_SPEC_SSB_DISABLE		3	/* Speculative Store Bypass disabled */
    #define PFA_SPEC_SSB_FORCE_DISABLE	4	/* Speculative Store Bypass force disabled*/
    #define PFA_SPEC_IB_DISABLE		5	/* Indirect branch speculation restricted */
    #define PFA_SPEC_IB_FORCE_DISABLE	6	/* Indirect branch speculation permanently restricted */
    #define PFA_SPEC_SSB_NOEXEC		7	/* Speculative Store Bypass clear on execve() */
    
    #define TASK_PFA_TEST(name, func)					
    	static inline bool task_##func(struct task_struct *p)		
    	{ return test_bit(PFA_##name, &p->atomic_flags); }
    
    #define TASK_PFA_SET(name, func)					
    	static inline void task_set_##func(struct task_struct *p)	
    	{ set_bit(PFA_##name, &p->atomic_flags); }
    
    #define TASK_PFA_CLEAR(name, func)					
    	static inline void task_clear_##func(struct task_struct *p)	
    	{ clear_bit(PFA_##name, &p->atomic_flags); }
    
    TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs)
    TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)
    
    TASK_PFA_TEST(SPREAD_PAGE, spread_page)
    TASK_PFA_SET(SPREAD_PAGE, spread_page)
    TASK_PFA_CLEAR(SPREAD_PAGE, spread_page)
    
    TASK_PFA_TEST(SPREAD_SLAB, spread_slab)
    TASK_PFA_SET(SPREAD_SLAB, spread_slab)
    TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
    
    TASK_PFA_TEST(SPEC_SSB_DISABLE, spec_ssb_disable)
    TASK_PFA_SET(SPEC_SSB_DISABLE, spec_ssb_disable)
    TASK_PFA_CLEAR(SPEC_SSB_DISABLE, spec_ssb_disable)
    
    TASK_PFA_TEST(SPEC_SSB_NOEXEC, spec_ssb_noexec)
    TASK_PFA_SET(SPEC_SSB_NOEXEC, spec_ssb_noexec)
    TASK_PFA_CLEAR(SPEC_SSB_NOEXEC, spec_ssb_noexec)
    
    TASK_PFA_TEST(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
    TASK_PFA_SET(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
    
    TASK_PFA_TEST(SPEC_IB_DISABLE, spec_ib_disable)
    TASK_PFA_SET(SPEC_IB_DISABLE, spec_ib_disable)
    TASK_PFA_CLEAR(SPEC_IB_DISABLE, spec_ib_disable)
    
    TASK_PFA_TEST(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
    TASK_PFA_SET(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
    
    static inline void
    current_restore_flags(unsigned long orig_flags, unsigned long flags)
    {
    	current->flags &= ~flags;
    	current->flags |= orig_flags & flags;
    }
    
    extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
    extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed);
    #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
    
    extern int 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);
    
    /**
     * task_nice - return the nice value of a given task.
     * @p: the task in question.
     *
     * Return: The nice value [ -20 ... 0 ... 19 ].
     */
    static inline int task_nice(const struct task_struct *p)
    {
    	return PRIO_TO_NICE((p)->static_prio);
    }
    
    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 available_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 int sched_setattr(struct task_struct *, const struct sched_attr *);
    extern int sched_setattr_nocheck(struct task_struct *, const struct sched_attr *);
    extern struct task_struct *idle_task(int cpu);
    
    /**
     * is_idle_task - is the specified task an idle task?
     * @p: the task in question.
     *
     * Return: 1 if @p is an idle task. 0 otherwise.
     */
    static inline bool is_idle_task(const struct task_struct *p)
    {
    	return !!(p->flags & PF_IDLE);
    }
    
    extern struct task_struct *curr_task(int cpu);
    extern void ia64_set_curr_task(int cpu, struct task_struct *p);
    
    void yield(void);
    
    union thread_union {
    #ifndef CONFIG_ARCH_TASK_STRUCT_ON_STACK
    	struct task_struct task;
    #endif
    #ifndef CONFIG_THREAD_INFO_IN_TASK
    	struct thread_info thread_info;
    #endif
    	unsigned long stack[THREAD_SIZE/sizeof(long)];
    };
    
    #ifndef CONFIG_THREAD_INFO_IN_TASK
    extern struct thread_info init_thread_info;
    #endif
    
    extern unsigned long init_stack[THREAD_SIZE / sizeof(unsigned long)];
    
    #ifdef CONFIG_THREAD_INFO_IN_TASK
    static inline struct thread_info *task_thread_info(struct task_struct *task)
    {
    	return &task->thread_info;
    }
    #elif !defined(__HAVE_THREAD_FUNCTIONS)
    # define task_thread_info(task)	((struct thread_info *)(task)->stack)
    #endif
    
    /*
     * 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);
    
    /*
     * find a task by its virtual pid and get the task struct
     */
    extern struct task_struct *find_get_task_by_vpid(pid_t nr);
    
    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 __set_task_comm(struct task_struct *tsk, const char *from, bool exec);
    
    static inline void set_task_comm(struct task_struct *tsk, const char *from)
    {
    	__set_task_comm(tsk, from, false);
    }
    
    extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk);
    #define get_task_comm(buf, tsk) ({			
    	BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN);	
    	__get_task_comm(buf, sizeof(buf), 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
    
    /*
     * 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 void update_tsk_thread_flag(struct task_struct *tsk, int flag,
    					  bool value)
    {
    	update_ti_thread_flag(task_thread_info(tsk), flag, value);
    }
    
    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));
    }
    
    /*
     * 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,
     */
    #ifndef CONFIG_PREEMPTION
    extern int _cond_resched(void);
    #else
    static inline int _cond_resched(void) { return 0; }
    #endif
    
    #define cond_resched() ({			
    	___might_sleep(__FILE__, __LINE__, 0);	
    	_cond_resched();			
    })
    
    extern int __cond_resched_lock(spinlock_t *lock);
    
    #define cond_resched_lock(lock) ({				
    	___might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);
    	__cond_resched_lock(lock);				
    })
    
    static inline void cond_resched_rcu(void)
    {
    #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
    	rcu_read_unlock();
    	cond_resched();
    	rcu_read_lock();
    #endif
    }
    
    /*
     * Does a critical section need to be broken due to another
     * task waiting?: (technically does not depend on CONFIG_PREEMPTION,
     * but a general need for low latency)
     */
    static inline int spin_needbreak(spinlock_t *lock)
    {
    #ifdef CONFIG_PREEMPTION
    	return spin_is_contended(lock);
    #else
    	return 0;
    #endif
    }
    
    static __always_inline bool need_resched(void)
    {
    	return unlikely(tif_need_resched());
    }
    
    /*
     * 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)
    {
    #ifdef CONFIG_THREAD_INFO_IN_TASK
    	return READ_ONCE(p->cpu);
    #else
    	return READ_ONCE(task_thread_info(p)->cpu);
    #endif
    }
    
    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 */
    
    /*
     * In order to reduce various lock holder preemption latencies provide an
     * interface to see if a vCPU is currently running or not.
     *
     * This allows us to terminate optimistic spin loops and block, analogous to
     * the native optimistic spin heuristic of testing if the lock owner task is
     * running or not.
     */
    #ifndef vcpu_is_preempted
    static inline bool vcpu_is_preempted(int cpu)
    {
    	return false;
    }
    #endif
    
    extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
    extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
    
    #ifndef TASK_SIZE_OF
    #define TASK_SIZE_OF(tsk)	TASK_SIZE
    #endif
    
    #ifdef CONFIG_RSEQ
    
    /*
     * Map the event mask on the user-space ABI enum rseq_cs_flags
     * for direct mask checks.
     */
    enum rseq_event_mask_bits {
    	RSEQ_EVENT_PREEMPT_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
    	RSEQ_EVENT_SIGNAL_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
    	RSEQ_EVENT_MIGRATE_BIT	= RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
    };
    
    enum rseq_event_mask {
    	RSEQ_EVENT_PREEMPT	= (1U << RSEQ_EVENT_PREEMPT_BIT),
    	RSEQ_EVENT_SIGNAL	= (1U << RSEQ_EVENT_SIGNAL_BIT),
    	RSEQ_EVENT_MIGRATE	= (1U << RSEQ_EVENT_MIGRATE_BIT),
    };
    
    static inline void rseq_set_notify_resume(struct task_struct *t)
    {
    	if (t->rseq)
    		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
    }
    
    void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
    
    static inline void rseq_handle_notify_resume(struct ksignal *ksig,
    					     struct pt_regs *regs)
    {
    	if (current->rseq)
    		__rseq_handle_notify_resume(ksig, regs);
    }
    
    static inline void rseq_signal_deliver(struct ksignal *ksig,
    				       struct pt_regs *regs)
    {
    	preempt_disable();
    	__set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask);
    	preempt_enable();
    	rseq_handle_notify_resume(ksig, regs);
    }
    
    /* rseq_preempt() requires preemption to be disabled. */
    static inline void rseq_preempt(struct task_struct *t)
    {
    	__set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
    	rseq_set_notify_resume(t);
    }
    
    /* rseq_migrate() requires preemption to be disabled. */
    static inline void rseq_migrate(struct task_struct *t)
    {
    	__set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
    	rseq_set_notify_resume(t);
    }
    
    /*
     * If parent process has a registered restartable sequences area, the
     * child inherits. Only applies when forking a process, not a thread.
     */
    static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
    {
    	if (clone_flags & CLONE_THREAD) {
    		t->rseq = NULL;
    		t->rseq_sig = 0;
    		t->rseq_event_mask = 0;
    	} else {
    		t->rseq = current->rseq;
    		t->rseq_sig = current->rseq_sig;
    		t->rseq_event_mask = current->rseq_event_mask;
    	}
    }
    
    static inline void rseq_execve(struct task_struct *t)
    {
    	t->rseq = NULL;
    	t->rseq_sig = 0;
    	t->rseq_event_mask = 0;
    }
    
    #else
    
    static inline void rseq_set_notify_resume(struct task_struct *t)
    {
    }
    static inline void rseq_handle_notify_resume(struct ksignal *ksig,
    					     struct pt_regs *regs)
    {
    }
    static inline void rseq_signal_deliver(struct ksignal *ksig,
    				       struct pt_regs *regs)
    {
    }
    static inline void rseq_preempt(struct task_struct *t)
    {
    }
    static inline void rseq_migrate(struct task_struct *t)
    {
    }
    static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
    {
    }
    static inline void rseq_execve(struct task_struct *t)
    {
    }
    
    #endif
    
    void __exit_umh(struct task_struct *tsk);
    
    static inline void exit_umh(struct task_struct *tsk)
    {
    	if (unlikely(tsk->flags & PF_UMH))
    		__exit_umh(tsk);
    }
    
    #ifdef CONFIG_DEBUG_RSEQ
    
    void rseq_syscall(struct pt_regs *regs);
    
    #else
    
    static inline void rseq_syscall(struct pt_regs *regs)
    {
    }
    
    #endif
    
    const struct sched_avg *sched_trace_cfs_rq_avg(struct cfs_rq *cfs_rq);
    char *sched_trace_cfs_rq_path(struct cfs_rq *cfs_rq, char *str, int len);
    int sched_trace_cfs_rq_cpu(struct cfs_rq *cfs_rq);
    
    const struct sched_avg *sched_trace_rq_avg_rt(struct rq *rq);
    const struct sched_avg *sched_trace_rq_avg_dl(struct rq *rq);
    const struct sched_avg *sched_trace_rq_avg_irq(struct rq *rq);
    
    int sched_trace_rq_cpu(struct rq *rq);
    
    const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
    
    #endif
    

      

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  • 原文地址:https://www.cnblogs.com/still-smile/p/12039998.html
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