sched.h

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

	/* Hash table maintenance information */
	struct list_head uidhash_list;
	uid_t uid;
};

extern struct user_struct *find_user(uid_t);

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

typedef struct prio_array prio_array_t;
struct backing_dev_info;
struct reclaim_state;

#ifdef CONFIG_SCHEDSTATS
struct sched_info {
	/* cumulative counters */
	unsigned long	cpu_time,	/* time spent on the cpu */
			run_delay,	/* time spent waiting on a runqueue */
			pcnt;		/* # of timeslices run on this cpu */

	/* timestamps */
	unsigned long	last_arrival,	/* when we last ran on a cpu */
			last_queued;	/* when we were last queued to run */
};

extern struct file_operations proc_schedstat_operations;
#endif

enum idle_type
{
	SCHED_IDLE,
	NOT_IDLE,
	NEWLY_IDLE,
	MAX_IDLE_TYPES
};

/*
 * sched-domains (multiprocessor balancing) declarations:
 */
#ifdef CONFIG_SMP
#define SCHED_LOAD_SCALE	128UL	/* increase resolution of load */

#define SD_LOAD_BALANCE		1	/* Do load balancing on this domain. */
#define SD_BALANCE_NEWIDLE	2	/* Balance when about to become idle */
#define SD_BALANCE_EXEC		4	/* Balance on exec */
#define SD_BALANCE_FORK		8	/* Balance on fork, clone */
#define SD_WAKE_IDLE		16	/* Wake to idle CPU on task wakeup */
#define SD_WAKE_AFFINE		32	/* Wake task to waking CPU */
#define SD_WAKE_BALANCE		64	/* Perform balancing at task wakeup */
#define SD_SHARE_CPUPOWER	128	/* Domain members share cpu power */

struct sched_group {
	struct sched_group *next;	/* Must be a circular list */
	cpumask_t cpumask;

	/*
	 * CPU power of this group, SCHED_LOAD_SCALE being max power for a
	 * single CPU. This is read only (except for setup, hotplug CPU).
	 */
	unsigned long cpu_power;
};

struct sched_domain {
	/* These fields must be setup */
	struct sched_domain *parent;	/* top domain must be null terminated */
	struct sched_group *groups;	/* the balancing groups of the domain */
	cpumask_t span;			/* span of all CPUs in this 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 long long cache_hot_time; /* Task considered cache hot (ns) */
	unsigned int cache_nice_tries;	/* Leave cache hot tasks for # tries */
	unsigned int per_cpu_gain;	/* CPU % gained by adding domain cpus */
	unsigned int busy_idx;
	unsigned int idle_idx;
	unsigned int newidle_idx;
	unsigned int wake_idx;
	unsigned int forkexec_idx;
	int flags;			/* See SD_* */

	/* 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 */

#ifdef CONFIG_SCHEDSTATS
	/* load_balance() stats */
	unsigned long lb_cnt[MAX_IDLE_TYPES];
	unsigned long lb_failed[MAX_IDLE_TYPES];
	unsigned long lb_balanced[MAX_IDLE_TYPES];
	unsigned long lb_imbalance[MAX_IDLE_TYPES];
	unsigned long lb_gained[MAX_IDLE_TYPES];
	unsigned long lb_hot_gained[MAX_IDLE_TYPES];
	unsigned long lb_nobusyg[MAX_IDLE_TYPES];
	unsigned long lb_nobusyq[MAX_IDLE_TYPES];

	/* Active load balancing */
	unsigned long alb_cnt;
	unsigned long alb_failed;
	unsigned long alb_pushed;

	/* SD_BALANCE_EXEC stats */
	unsigned long sbe_cnt;
	unsigned long sbe_balanced;
	unsigned long sbe_pushed;

	/* SD_BALANCE_FORK stats */
	unsigned long sbf_cnt;
	unsigned long sbf_balanced;
	unsigned long sbf_pushed;

	/* try_to_wake_up() stats */
	unsigned long ttwu_wake_remote;
	unsigned long ttwu_move_affine;
	unsigned long ttwu_move_balance;
#endif
};

extern void partition_sched_domains(cpumask_t *partition1,
				    cpumask_t *partition2);
#endif /* CONFIG_SMP */


struct io_context;			/* See blkdev.h */
void exit_io_context(void);
struct cpuset;

#define NGROUPS_SMALL		32
#define NGROUPS_PER_BLOCK	((int)(PAGE_SIZE / sizeof(gid_t)))
struct group_info {
	int ngroups;
	atomic_t usage;
	gid_t small_block[NGROUPS_SMALL];
	int nblocks;
	gid_t *blocks[0];
};

/*
 * get_group_info() must be called with the owning task locked (via task_lock())
 * when task != current.  The reason being that the vast majority of callers are
 * looking at current->group_info, which can not be changed except by the
 * current task.  Changing current->group_info requires the task lock, too.
 */
#define get_group_info(group_info) do { \
	atomic_inc(&(group_info)->usage); \
} while (0)

#define put_group_info(group_info) do { \
	if (atomic_dec_and_test(&(group_info)->usage)) \
		groups_free(group_info); \
} while (0)

extern struct group_info *groups_alloc(int gidsetsize);
extern void groups_free(struct group_info *group_info);
extern int set_current_groups(struct group_info *group_info);
extern int groups_search(struct group_info *group_info, gid_t grp);
/* access the groups "array" with this macro */
#define GROUP_AT(gi, i) \
    ((gi)->blocks[(i)/NGROUPS_PER_BLOCK][(i)%NGROUPS_PER_BLOCK])

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

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

struct task_struct {
	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */
	struct thread_info *thread_info;
	atomic_t usage;
	unsigned long flags;	/* per process flags, defined below */
	unsigned long ptrace;

	int lock_depth;		/* BKL lock depth */

#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
	int oncpu;
#endif
	int prio, static_prio;
	struct list_head run_list;
	prio_array_t *array;

	unsigned short ioprio;

	unsigned long sleep_avg;
	unsigned long long timestamp, last_ran;
	unsigned long long sched_time; /* sched_clock time spent running */
	int activated;

	unsigned long policy;
	cpumask_t cpus_allowed;
	unsigned int time_slice, first_time_slice;

#ifdef CONFIG_SCHEDSTATS
	struct sched_info sched_info;
#endif

	struct list_head tasks;
	/*
	 * ptrace_list/ptrace_children forms the list of my children
	 * that were stolen by a ptracer.
	 */
	struct list_head ptrace_children;
	struct list_head ptrace_list;

	struct mm_struct *mm, *active_mm;

/* task state */
	struct linux_binfmt *binfmt;
	long exit_state;
	int exit_code, exit_signal;
	int pdeath_signal;  /*  The signal sent when the parent dies  */
	/* ??? */
	unsigned long personality;
	unsigned did_exec:1;
	pid_t pid;
	pid_t tgid;
	/* 
	 * pointers to (original) parent process, youngest child, younger sibling,
	 * older sibling, respectively.  (p->father can be replaced with 
	 * p->parent->pid)
	 */
	struct task_struct *real_parent; /* real parent process (when being debugged) */
	struct task_struct *parent;	/* parent process */
	/*
	 * children/sibling forms the list of my children plus the
	 * tasks I'm ptracing.
	 */
	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 */

	/* PID/PID hash table linkage. */
	struct pid pids[PIDTYPE_MAX];

	struct completion *vfork_done;		/* for vfork() */
	int __user *set_child_tid;		/* CLONE_CHILD_SETTID */
	int __user *clear_child_tid;		/* CLONE_CHILD_CLEARTID */

	unsigned long rt_priority;
	cputime_t utime, stime;
	unsigned long nvcsw, nivcsw; /* context switch counts */
	struct timespec start_time;
/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
	unsigned long min_flt, maj_flt;

  	cputime_t it_prof_expires, it_virt_expires;
	unsigned long long it_sched_expires;
	struct list_head cpu_timers[3];

/* process credentials */
	uid_t uid,euid,suid,fsuid;
	gid_t gid,egid,sgid,fsgid;
	struct group_info *group_info;
	kernel_cap_t   cap_effective, cap_inheritable, cap_permitted;
	unsigned keep_capabilities:1;
	struct user_struct *user;
#ifdef CONFIG_KEYS
	struct key *thread_keyring;	/* keyring private to this thread */
	unsigned char jit_keyring;	/* default keyring to attach requested keys to */
#endif
	int oomkilladj; /* OOM kill score adjustment (bit shift). */
	char comm[TASK_COMM_LEN]; /* executable name excluding path
				     - access with [gs]et_task_comm (which lock
				       it with task_lock())
				     - initialized normally by flush_old_exec */
/* file system info */
	int link_count, total_link_count;
/* ipc stuff */
	struct sysv_sem sysvsem;
/* CPU-specific state of this task */
	struct thread_struct thread;
/* filesystem information */
	struct fs_struct *fs;
/* open file information */
	struct files_struct *files;
/* namespace */
	struct namespace *namespace;
/* signal handlers */
	struct signal_struct *signal;
	struct sighand_struct *sighand;

	sigset_t blocked, real_blocked;
	struct sigpending pending;

	unsigned long sas_ss_sp;
	size_t sas_ss_size;
	int (*notifier)(void *priv);
	void *notifier_data;
	sigset_t *notifier_mask;
	
	void *security;
	struct audit_context *audit_context;
	seccomp_t seccomp;

/* Thread group tracking */
   	u32 parent_exec_id;
   	u32 self_exec_id;
/* Protection of (de-)allocation: mm, files, fs, tty, keyrings */
	spinlock_t alloc_lock;
/* Protection of proc_dentry: nesting proc_lock, dcache_lock, write_lock_irq(&tasklist_lock); */
	spinlock_t proc_lock;

/* journalling filesystem info */
	void *journal_info;

/* VM state */
	struct reclaim_state *reclaim_state;

	struct dentry *proc_dentry;
	struct backing_dev_info *backing_dev_info;

	struct io_context *io_context;

	unsigned long ptrace_message;
	siginfo_t *last_siginfo; /* For ptrace use.  */
/*
 * current io wait handle: wait queue entry to use for io waits
 * If this thread is processing aio, this points at the waitqueue
 * inside the currently handled kiocb. It may be NULL (i.e. default
 * to a stack based synchronous wait) if its doing sync IO.
 */
	wait_queue_t *io_wait;
/* i/o counters(bytes read/written, #syscalls */
	u64 rchar, wchar, syscr, syscw;
#if defined(CONFIG_BSD_PROCESS_ACCT)
	u64 acct_rss_mem1;	/* accumulated rss usage */
	u64 acct_vm_mem1;	/* accumulated virtual memory usage */
	clock_t acct_stimexpd;	/* clock_t-converted stime since last update */
#endif
#ifdef CONFIG_NUMA
  	struct mempolicy *mempolicy;
	short il_next;
#endif
#ifdef CONFIG_CPUSETS
	struct cpuset *cpuset;
	nodemask_t mems_allowed;
	int cpuset_mems_generation;
#endif
	atomic_t fs_excl;	/* holding fs exclusive resources */
};

static inline pid_t process_group(struct task_struct *tsk)
{
	return tsk->signal->pgrp;
}

/**
 * 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].nr != 0;
}

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

/*
 * Per process flags
 */
#define PF_ALIGNWARN	0x00000001	/* Print alignment warning msgs */
					/* Not implemented yet, only for 486*/
#define PF_STARTING	0x00000002	/* being created */
#define PF_EXITING	0x00000004	/* getting shut down */
#define PF_DEAD		0x00000008	/* Dead */
#define PF_FORKNOEXEC	0x00000040	/* forked but didn't exec */
#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_FLUSHER	0x00001000	/* responsible for disk writeback */
#define PF_USED_MATH	0x00002000	/* if unset the fpu must be initialized before use */
#define PF_FREEZE	0x00004000	/* this task is being frozen for suspend now */
#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_SWAPOFF	0x00080000	/* I am in swapoff */
#define PF_LESS_THROTTLE 0x00100000	/* Throttle me less: I clean memory */
#define PF_SYNCWRITE	0x00200000	/* I am doing a sync write */
#define PF_BORROWED_MM	0x00400000	/* I am a kthread doing use_mm */
#define PF_RANDOMIZE	0x00800000	/* randomize virtual address space */

/*
 * 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)

#ifdef CONFIG_SMP
extern int set_cpus_allowed(task_t *p, cpumask_t new_mask);
#else
static inline int set_cpus_allowed(task_t *p, cpumask_t new_mask)
{
	if (!cpus_intersects(new_mask, cpu_online_map))
		return -EINVAL;
	return 0;
}
#endif

extern unsigned long long sched_clock(void);
extern unsigned long long current_sched_time(const task_t *current_task);

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

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

extern void sched_idle_next(void);
extern void set_user_nice(task_t *p, long nice);
extern int task_prio(const task_t *p);
extern int task_nice(const task_t *p);
extern int can_nice(const task_t *p, const int nice);
extern int task_curr(const task_t *p);
extern int idle_cpu(int cpu);
extern int sched_setscheduler(struct task_struct *, int, struct sched_param *);
extern task_t *idle_task(int cpu);
extern task_t *curr_task(int cpu);
extern void set_curr_task(int cpu, task_t *p);

void yield(void);