RT-Thread Thread

結構

File: rtdef.h

/**
 * Thread structure
 */
struct rt_thread
{
    /* rt object */
    char        name[RT_NAME_MAX];                      /**< the name of thread */
    rt_uint8_t  type;                                   /**< type of object */
    rt_uint8_t  flags;                                  /**< thread's flags */

#ifdef RT_USING_MODULE
    void       *module_id;                              /**< id of application module */
#endif

• 一些基本資料，如名字等

    rt_list_t   list;                                   /**< the object list */
    rt_list_t   tlist;                                  /**< the thread list */

• 兩條鏈：thread list、object list

    /* stack point and entry */
    void       *sp;                                     /**< stack point */
    void       *entry;                                  /**< entry */
    void       *parameter;                              /**< parameter */
    void       *stack_addr;                             /**< stack address */
    rt_uint32_t stack_size;                             /**< stack size */

• stack 相關的

    /* error code */
    rt_err_t    error;                                  /**< error code */

    rt_uint8_t  stat;                                   /**< thread status */

• 狀態，下面會列出來所有可能

    /* priority */
    rt_uint8_t  current_priority;                       /**< current priority */
    rt_uint8_t  init_priority;                          /**< initialized priority */
#if RT_THREAD_PRIORITY_MAX > 32
    rt_uint8_t  number;
    rt_uint8_t  high_mask;
#endif
    rt_uint32_t number_mask;

• 與權限相關的

#if defined(RT_USING_EVENT)
    /* thread event */
    rt_uint32_t event_set;
    rt_uint8_t  event_info;
#endif

#if defined(RT_USING_SIGNALS)
    rt_sigset_t     sig_pending;                        /**< the pending signals */
    rt_sigset_t     sig_mask;                           /**< the mask bits of signal */

    void            *sig_ret;                           /**< the return stack pointer from signal */
    rt_sighandler_t *sig_vectors;                       /**< vectors of signal handler */
    void            *si_list;                           /**< the signal infor list */
#endif

    rt_ubase_t  init_tick;                              /**< thread's initialized tick */
    rt_ubase_t  remaining_tick;                         /**< remaining tick */

    struct rt_timer thread_timer;                       /**< built-in thread timer */

• event、sig、tick

    void (*cleanup)(struct rt_thread *tid);             /**< cleanup function when thread exit */

    /* light weight process if present */
#ifdef RT_USING_LWP
    void        *lwp;
#endif

    rt_uint32_t user_data;                             /**< private user data beyond this thread */
};
typedef struct rt_thread *rt_thread_t;

• cleanup 函數及 user_data

---

狀態

• 一共有 6 種狀態

#define RT_THREAD_INIT                  0x00                /**< Initialized status */
#define RT_THREAD_READY                 0x01                /**< Ready status */
#define RT_THREAD_SUSPEND               0x02                /**< Suspend status */
#define RT_THREAD_RUNNING               0x03                /**< Running status */
#define RT_THREAD_BLOCK                 RT_THREAD_SUSPEND   /**< Blocked status */
#define RT_THREAD_CLOSE                 0x04                /**< Closed status */
#define RT_THREAD_STAT_MASK             0x0f

---

File: thread.h

• 下圖為官方文本的 thread 流向圖，接著一個一個的看下去
  

---

初始化、建立 thread

靜態記憶體管理

rt_thread_init

功能	回傳值
初始化 thread	RT-EOK

*thread	*name	*entry	*parameter
thread 本體	名字	要執行的副程式	副程式參數

*stack_start	stack_size	priority	tick
thread 堆疊起點	thread 堆疊大小	優先級	可執行的 tick 數

/**
 * This function will initialize a thread, normally it's used to initialize a
 * static thread object.
 *
 * @param thread the static thread object
 * @param name the name of thread, which shall be unique
 * @param entry the entry function of thread
 * @param parameter the parameter of thread enter function
 * @param stack_start the start address of thread stack
 * @param stack_size the size of thread stack
 * @param priority the priority of thread
 * @param tick the time slice if there are same priority thread
 *
 * @return the operation status, RT_EOK on OK, -RT_ERROR on error
 */
rt_err_t rt_thread_init(struct rt_thread *thread,
                        const char       *name,
                        void (*entry)(void *parameter),
                        void             *parameter,
                        void             *stack_start,
                        rt_uint32_t       stack_size,
                        rt_uint8_t        priority,
                        rt_uint32_t       tick)
{
    /* thread check */
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(stack_start != RT_NULL);

    /* init thread object */
    rt_object_init((rt_object_t)thread, RT_Object_Class_Thread, name);

    return _rt_thread_init(thread,
                           name,
                           entry,
                           parameter,
                           stack_start,
                           stack_size,
                           priority,
                           tick);
}
RTM_EXPORT(rt_thread_init);

• 透過 _rt_thread_init 完成初始化

---

_rt_thread_init

功能	回傳值
初始化 thread	RT_EOK

*thread	*name	*entry	*parameter
thread 本體	名字	要執行的副程式	副程式參數

*stack_start	stack_size	priority	tick
thread 堆疊起點	thread 堆疊大小	優先級	可執行的 tick 數

static rt_err_t _rt_thread_init(struct rt_thread *thread,
                                const char       *name,
                                void (*entry)(void *parameter),
                                void             *parameter,
                                void             *stack_start,
                                rt_uint32_t       stack_size,
                                rt_uint8_t        priority,
                                rt_uint32_t       tick)
{
    /* init thread list */
    rt_list_init(&(thread->tlist));

    thread->entry = (void *)entry;
    thread->parameter = parameter;

    /* stack init */
    thread->stack_addr = stack_start;
    thread->stack_size = stack_size;

• 首先將傳入的資料填入結構

    /* init thread stack */
    rt_memset(thread->stack_addr, '#', thread->stack_size);
    thread->sp = (void *)rt_hw_stack_init(thread->entry, thread->parameter,
                                          (void *)((char *)thread->stack_addr + thread->stack_size - 4),
                                          (void *)rt_thread_exit);

• 接著設定堆疊，使用 rt_hw_stack_init 來完成（根據不同 cpu 有不同的方式，rt_hw_stack_init 在 /libcpu 中針對不同的 cpu 有不同的函式宣告）

    /* priority init */
    RT_ASSERT(priority < RT_THREAD_PRIORITY_MAX);
    thread->init_priority    = priority;
    thread->current_priority = priority;

    thread->number_mask = 0;
#if RT_THREAD_PRIORITY_MAX > 32
    thread->number = 0;
    thread->high_mask = 0;
#endif

• 設定 priority 及 mask

    /* tick init */
    thread->init_tick      = tick;
    thread->remaining_tick = tick;

    /* error and flags */
    thread->error = RT_EOK;
    thread->stat  = RT_THREAD_INIT;

    /* initialize cleanup function and user data */
    thread->cleanup   = 0;
    thread->user_data = 0;

    /* init thread timer */
    rt_timer_init(&(thread->thread_timer),
                  thread->name,
                  rt_thread_timeout,
                  thread,
                  0,
                  RT_TIMER_FLAG_ONE_SHOT);

    /* initialize signal */
#ifdef RT_USING_SIGNALS
    thread->sig_mask    = 0x00;
    thread->sig_pending = 0x00;

    thread->sig_ret     = RT_NULL;
    thread->sig_vectors = RT_NULL;
    thread->si_list     = RT_NULL;
#endif

#ifdef RT_USING_LWP
    thread->lwp = RT_NULL;
#endif

    RT_OBJECT_HOOK_CALL(rt_thread_inited_hook, (thread));

    return RT_EOK;
}

• 最後依序完成 tick、sig、hook 等的初始化

---

動態記憶體管理

rt_thread_create

功能	回傳值
建立 thread	thread

*name	*entry	*parameter
名字	要執行的副程式	副程式參數

*stack_start	stack_size	priority	tick
thread 堆疊起點	thread 堆疊大小	優先級	可執行的 tick 數

/**
 * This function will create a thread object and allocate thread object memory
 * and stack.
 *
 * @param name the name of thread, which shall be unique
 * @param entry the entry function of thread
 * @param parameter the parameter of thread enter function
 * @param stack_size the size of thread stack
 * @param priority the priority of thread
 * @param tick the time slice if there are same priority thread
 *
 * @return the created thread object
 */
rt_thread_t rt_thread_create(const char *name,
                             void (*entry)(void *parameter),
                             void       *parameter,
                             rt_uint32_t stack_size,
                             rt_uint8_t  priority,
                             rt_uint32_t tick)
{
    struct rt_thread *thread;
    void *stack_start;

    thread = (struct rt_thread *)rt_object_allocate(RT_Object_Class_Thread,
                                                    name);
    if (thread == RT_NULL)
        return RT_NULL;

    stack_start = (void *)RT_KERNEL_MALLOC(stack_size);
    if (stack_start == RT_NULL)
    {
        /* allocate stack failure */
        rt_object_delete((rt_object_t)thread);

        return RT_NULL;
    }

    _rt_thread_init(thread,
                    name,
                    entry,
                    parameter,
                    stack_start,
                    stack_size,
                    priority,
                    tick);

    return thread;
}
RTM_EXPORT(rt_thread_create);

• 首先 allocate 一塊給 thread，一塊給堆疊
• 再呼叫 _rt_thread_init 完成初始化

---

啟動 thread

rt_thread_startup

功能	回傳值
啟動 thread	RT_EOK

thread
欲啟動的 thread

/**
 * This function will start a thread and put it to system ready queue
 *
 * @param thread the thread to be started
 *
 * @return the operation status, RT_EOK on OK, -RT_ERROR on error
 */
rt_err_t rt_thread_startup(rt_thread_t thread)
{
    /* thread check */
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT((thread->stat & RT_THREAD_STAT_MASK) == RT_THREAD_INIT);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);

    /* set current priority to init priority */
    thread->current_priority = thread->init_priority;

• 設定 priority

    /* calculate priority attribute */
#if RT_THREAD_PRIORITY_MAX > 32
    thread->number      = thread->current_priority >> 3;            /* 5bit */
    thread->number_mask = 1L << thread->number;
    thread->high_mask   = 1L << (thread->current_priority & 0x07);  /* 3bit */
#else
    thread->number_mask = 1L << thread->current_priority;
#endif

• 這些參數是用來計算權限的，scheudler 會用到

    RT_DEBUG_LOG(RT_DEBUG_THREAD, ("startup a thread:%s with priority:%d\n",
                                   thread->name, thread->init_priority));
    /* change thread stat */
    thread->stat = RT_THREAD_SUSPEND;
    /* then resume it */
    rt_thread_resume(thread);
    if (rt_thread_self() != RT_NULL)
    {
        /* do a scheduling */
        rt_schedule();
    }

    return RT_EOK;
}
RTM_EXPORT(rt_thread_startup);

• 最後將 stat 設為 RT_THREAD_SUSPEND，再透過 rt_thread_resume 來完成啟動
• 啟動完成後呼叫 rt_scheduler() 來執行一次調度

---

暫停、復原 thread

rt_thread_suspend

功能	回傳值
暫停 thread	RT-EOK

*thread
欲暫停的 thread

/**
 * This function will suspend the specified thread.
 *
 * @param thread the thread to be suspended
 *
 * @return the operation status, RT_EOK on OK, -RT_ERROR on error
 *
 * @note if suspend self thread, after this function call, the
 * rt_schedule() must be invoked.
 */
rt_err_t rt_thread_suspend(rt_thread_t thread)
{
    register rt_base_t temp;

    /* thread check */
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);

    RT_DEBUG_LOG(RT_DEBUG_THREAD, ("thread suspend:  %s\n", thread->name));

    if ((thread->stat & RT_THREAD_STAT_MASK) != RT_THREAD_READY)
    {
        RT_DEBUG_LOG(RT_DEBUG_THREAD, ("thread suspend: thread disorder, 0x%2x\n",
                                       thread->stat));

        return -RT_ERROR;
    }

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();

    /* change thread stat */
    thread->stat = RT_THREAD_SUSPEND | (thread->stat & ~RT_THREAD_STAT_MASK);
    rt_schedule_remove_thread(thread);

    /* stop thread timer anyway */
    rt_timer_stop(&(thread->thread_timer));

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    RT_OBJECT_HOOK_CALL(rt_thread_suspend_hook, (thread));
    return RT_EOK;
}
RTM_EXPORT(rt_thread_suspend);

• 首先將狀態修改為 RT_THREAD_SUSPEND，接著將 thread 從 tlist 移除，結束 timer

---

rt_thread_delay

功能	回傳值
延遲 thread	RT-EOK

tick
欲延遲的時間

/**
 * This function will let current thread delay for some ticks.
 *
 * @param tick the delay ticks
 *
 * @return RT_EOK
 */
rt_err_t rt_thread_delay(rt_tick_t tick)
{
    return rt_thread_sleep(tick);
}
RTM_EXPORT(rt_thread_delay);

• 透過 rt_thread_sleep 實作

---

rt_thread_sleep

功能	回傳值
使 thread 休眠	RT-EOK

tick
欲睡眠的時間

/**
 * This function will let current thread sleep for some ticks.
 *
 * @param tick the sleep ticks
 *
 * @return RT_EOK
 */
rt_err_t rt_thread_sleep(rt_tick_t tick)
{
    register rt_base_t temp;
    struct rt_thread *thread;

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();
    /* set to current thread */
    thread = rt_current_thread;
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);

    /* suspend thread */
    rt_thread_suspend(thread);

    /* reset the timeout of thread timer and start it */
    rt_timer_control(&(thread->thread_timer), RT_TIMER_CTRL_SET_TIME, &tick);
    rt_timer_start(&(thread->thread_timer));

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    rt_schedule();

    /* clear error number of this thread to RT_EOK */
    if (thread->error == -RT_ETIMEOUT)
        thread->error = RT_EOK;

    return RT_EOK;
}

---

復原 thread

rt_thread_resume

功能	回傳值
復原 thread	RT-EOK

*thread
欲復原的 thread

/**
 * This function will resume a thread and put it to system ready queue.
 *
 * @param thread the thread to be resumed
 *
 * @return the operation status, RT_EOK on OK, -RT_ERROR on error
 */
rt_err_t rt_thread_resume(rt_thread_t thread)
{
    register rt_base_t temp;

    /* thread check */
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);

    RT_DEBUG_LOG(RT_DEBUG_THREAD, ("thread resume:  %s\n", thread->name));

    if ((thread->stat & RT_THREAD_STAT_MASK) != RT_THREAD_SUSPEND)
    {
        RT_DEBUG_LOG(RT_DEBUG_THREAD, ("thread resume: thread disorder, %d\n",
                                       thread->stat));

        return -RT_ERROR;
    }

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();

    /* remove from suspend list */
    rt_list_remove(&(thread->tlist));

    rt_timer_stop(&thread->thread_timer);

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    /* insert to schedule ready list */
    rt_schedule_insert_thread(thread);

    RT_OBJECT_HOOK_CALL(rt_thread_resume_hook, (thread));
    return RT_EOK;
}
RTM_EXPORT(rt_thread_resume);

• 首先從 suspend list 移除，停止 timer，掛回去 ready list
• rt_schedule_insert_thread 會將狀態修改成 RT_THREAD_READY

---

離開、刪除 thread

rt_thread_exit

功能	回傳值
暫停 thread	void

void rt_thread_exit(void)
{
    struct rt_thread *thread;
    register rt_base_t level;

    /* get current thread */
    thread = rt_current_thread;

    /* disable interrupt */
    level = rt_hw_interrupt_disable();

    /* remove from schedule */
    rt_schedule_remove_thread(thread);
    /* change stat */
    thread->stat = RT_THREAD_CLOSE;

    /* remove it from timer list */
    rt_timer_detach(&thread->thread_timer);

• 首先從 ready list 中移除，修改狀態為 RT_THREAD_CLOSE，從 timer list 中移除

    if ((rt_object_is_systemobject((rt_object_t)thread) == RT_TRUE) &&
        thread->cleanup == RT_NULL)
    {
        rt_object_detach((rt_object_t)thread);
    }
    else
    {
        /* insert to defunct thread list */
        rt_list_insert_after(&rt_thread_defunct, &(thread->tlist));
    }

    /* enable interrupt */
    rt_hw_interrupt_enable(level);

    /* switch to next task */
    rt_schedule();
}

• 如果為系統的 thread，且 cleanup 函式沒有被定義時，呼叫 rt_object_detach 來完成移除的動作
• 否則，將 thread 插入至 rt_thread_defunct，此鏈上面的 thread 會由 idle 清除。

---

刪除 thread

動態記憶體管理

rt_thread_delete

功能	回傳值
刪除 thread	RT-EOK

*thread
欲刪除的 thread

/**
 * This function will delete a thread. The thread object will be removed from
 * thread queue and deleted from system object management in the idle thread.
 *
 * @param thread the thread to be deleted
 *
 * @return the operation status, RT_EOK on OK, -RT_ERROR on error
 */
rt_err_t rt_thread_delete(rt_thread_t thread)
{
    rt_base_t lock;

    /* thread check */
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);
    RT_ASSERT(rt_object_is_systemobject((rt_object_t)thread) == RT_FALSE);

    if ((thread->stat & RT_THREAD_STAT_MASK) != RT_THREAD_INIT)
    {
        /* remove from schedule */
        rt_schedule_remove_thread(thread);
    }

• 如果此 thread 已經啟動過了，將此 thread 從 ready list 移除

    /* release thread timer */
    rt_timer_detach(&(thread->thread_timer));

    /* change stat */
    thread->stat = RT_THREAD_CLOSE;

    /* disable interrupt */
    lock = rt_hw_interrupt_disable();

    /* insert to defunct thread list */
    rt_list_insert_after(&rt_thread_defunct, &(thread->tlist));

    /* enable interrupt */
    rt_hw_interrupt_enable(lock);

    return RT_EOK;
}
RTM_EXPORT(rt_thread_delete);

• 接著將 timer 還回去，修改狀態為 RT_THREAD_CLOSE，插入至 rt_thread_defunct

---

靜態記憶體管理

rt_thread_detach

功能	回傳值
刪除 thread	RT-EOK

*thread
欲刪除的 thread

/**
 * This function will detach a thread. The thread object will be removed from
 * thread queue and detached/deleted from system object management.
 *
 * @param thread the thread to be deleted
 *
 * @return the operation status, RT_EOK on OK, -RT_ERROR on error
 */
rt_err_t rt_thread_detach(rt_thread_t thread)
{
    rt_base_t lock;

    /* thread check */
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);
    RT_ASSERT(rt_object_is_systemobject((rt_object_t)thread));

    if ((thread->stat & RT_THREAD_STAT_MASK) != RT_THREAD_INIT)
    {
        /* remove from schedule */
        rt_schedule_remove_thread(thread);
    }

    /* release thread timer */
    rt_timer_detach(&(thread->thread_timer));

    /* change stat */
    thread->stat = RT_THREAD_CLOSE;

    /* detach object */
    rt_object_detach((rt_object_t)thread);

    if (thread->cleanup != RT_NULL)
    {
        /* disable interrupt */
        lock = rt_hw_interrupt_disable();

        /* insert to defunct thread list */
        rt_list_insert_after(&rt_thread_defunct, &(thread->tlist));

        /* enable interrupt */
        rt_hw_interrupt_enable(lock);
    }

    return RT_EOK;
}
RTM_EXPORT(rt_thread_detach);

• 與 delete 不同的差在第32行

控制 thread

rt_thread_control

功能	回傳值
控制 thread	RT-EOK

*thread	cmd	*argv
欲控制的 thread	需執行的動作	伴隨動作的參數

/**
 * This function will control thread behaviors according to control command.
 *
 * @param thread the specified thread to be controlled
 * @param cmd the control command, which includes
 *  RT_THREAD_CTRL_CHANGE_PRIORITY for changing priority level of thread;
 *  RT_THREAD_CTRL_STARTUP for starting a thread;
 *  RT_THREAD_CTRL_CLOSE for delete a thread.
 * @param arg the argument of control command
 *
 * @return RT_EOK
 */
rt_err_t rt_thread_control(rt_thread_t thread, int cmd, void *arg)
{
    register rt_base_t temp;

    /* thread check */
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);

    switch (cmd)
    {
    case RT_THREAD_CTRL_CHANGE_PRIORITY:
        /* disable interrupt */
        temp = rt_hw_interrupt_disable();

        /* for ready thread, change queue */
        if ((thread->stat & RT_THREAD_STAT_MASK) == RT_THREAD_READY)
        {
            /* remove thread from schedule queue first */
            rt_schedule_remove_thread(thread);

            /* change thread priority */
            thread->current_priority = *(rt_uint8_t *)arg;

            /* recalculate priority attribute */
#if RT_THREAD_PRIORITY_MAX > 32
            thread->number      = thread->current_priority >> 3;            /* 5bit */
            thread->number_mask = 1 << thread->number;
            thread->high_mask   = 1 << (thread->current_priority & 0x07);   /* 3bit */
#else
            thread->number_mask = 1 << thread->current_priority;
#endif

            /* insert thread to schedule queue again */
            rt_schedule_insert_thread(thread);
        }
        else
        {
            thread->current_priority = *(rt_uint8_t *)arg;

            /* recalculate priority attribute */
#if RT_THREAD_PRIORITY_MAX > 32
            thread->number      = thread->current_priority >> 3;            /* 5bit */
            thread->number_mask = 1 << thread->number;
            thread->high_mask   = 1 << (thread->current_priority & 0x07);   /* 3bit */
#else
            thread->number_mask = 1 << thread->current_priority;
#endif
        }

        /* enable interrupt */
        rt_hw_interrupt_enable(temp);
        break;

    case RT_THREAD_CTRL_STARTUP:
        return rt_thread_startup(thread);

#ifdef RT_USING_HEAP
    case RT_THREAD_CTRL_CLOSE:
        return rt_thread_delete(thread);
#endif

    default:
        break;
    }

    return RT_EOK;
}
RTM_EXPORT(rt_thread_control);

tags: RT-Thread kernel thread