嵌入式操作系统内核原理和开发（线程状态）
2023-09-27 14:27:10 时间
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从第一篇的os博客以来，谈了很多内容，有中断、切换、调度、内存、互斥和延时等等，但是线程的状态却没有涉及到，今天我们要好好说一说。说到线程的状态，按照一般的说法，主要包括就绪、延时、阻塞、阻塞超时四个状态。如果线程没有死亡的话，那么这几个状态也够用了，但是我们后来发现可能需要对某些线程进行挂起处理，这可能是出现了故障或者是为了调试使用。因此，除了上面的四个状态，我们还要补充对应的四个挂起状态，分别是挂起、延时挂起、阻塞挂起、阻塞延时挂起。
说到了线程状态，下面我们就看看常见的线程处理函数有哪些，无外乎线程创建、线程延时、线程挂起、线程恢复和线程删除等等。
RAW_U16 raw_task_create(RAW_TASK_OBJ *task_obj, RAW_U8 *task_name, RAW_VOID *task_arg,
RAW_U8 task_prio, RAW_U16 time_slice, PORT_STACK *task_stack_base,
RAW_U32 stack_size, RAW_TASK_ENTRY task_entry, RAW_U8 auto_start)
{
#if (RAW_TASK_STACK_CHECK > 0)
PORT_STACK *p_stack;
RAW_U32 i;
#endif
RAW_SR_ALLOC();
#if (RAW_TASK_FUNCTION_CHECK > 0)
if (task_obj == 0) {
return RAW_NULL_OBJECT;
}
if (task_prio >= CONFIG_RAW_PRIO_MAX) {
return RAW_BYOND_MAX_PRIORITY;
}
if (task_stack_base == 0) {
return RAW_NULL_POINTER;
}
if (task_entry == 0) {
return RAW_NULL_POINTER;
}
#endif
RAW_CRITICAL_ENTER();
if (task_prio == IDLE_PRIORITY) {
if (idle_task_exit) {
RAW_CRITICAL_EXIT();
return RAW_IDLE_EXIT;
}
idle_task_exit = 1;
}
RAW_CRITICAL_EXIT();
raw_memset(task_obj, 0, sizeof(RAW_TASK_OBJ));
#if (CONFIG_ROUND_ROBIN > 0)
if (time_slice) {
task_obj->time_total = time_slice;
}
else {
task_obj->time_total = TIME_SLICE_DEFAULT;
}
task_obj->time_slice = task_obj->time_total;
#endif
if (auto_start)
task_obj->task_state = RAW_RDY;
else
task_obj->task_state = RAW_SUSPENDED;
#if (RAW_TASK_STACK_CHECK > 0)
task_obj->task_stack_base = task_stack_base;
p_stack = task_stack_base;
for (i = 0; i < stack_size; i++) {
*p_stack++ =0;
}
#endif
task_obj->task_stack = port_stack_init(task_stack_base, stack_size, task_arg, task_entry);
task_obj->task_name = task_name;
task_obj->priority = task_prio;
task_create_hook(task_obj);
RAW_CRITICAL_ENTER();
#if (RAW_TASK_STACK_CHECK > 0)
task_obj->stack_size = stack_size;
list_insert(&task_head, &task_obj->stack_check_list);
#endif
if (auto_start) {
add_ready_list_end(&raw_ready_queue, task_obj);
}
if (raw_os_active != RAW_OS_RUNNING) { /* Return if multitasking has not started */
RAW_CRITICAL_EXIT();
return RAW_OS_STOPPED;
}
RAW_CRITICAL_EXIT();
if (auto_start) {
raw_sched();
}
return RAW_SUCCESS;
}
RAW_U16 raw_sleep(RAW_U32 dly)
{
RAW_U16 error_status;
RAW_SR_ALLOC();
#if (RAW_TASK_FUNCTION_CHECK > 0)
if (raw_int_nesting) {
return RAW_NOT_CALLED_BY_ISR;
}
#endif
RAW_CRITICAL_ENTER();
if (dly) {
/*system is locked so task can not sleep just return immediately*/
if (raw_sched_lock) {
RAW_CRITICAL_EXIT();
return RAW_SCHED_DISABLE;
}
raw_task_active->task_state = RAW_DLY;
tick_list_insert(raw_task_active, dly);
remove_ready_list(&raw_ready_queue, raw_task_active);
}
else {
/*make current task to the end of ready list*/
move_to_ready_list_end(&raw_ready_queue, raw_task_active);
}
RAW_CRITICAL_EXIT();
raw_sched();
if (dly) {
/*task is timeout after sleep*/
error_status = block_state_post_process(raw_task_active, 0);
}
else {
error_status = RAW_SUCCESS;
}
return error_status;
}
RAW_U16 raw_task_suspend(RAW_TASK_OBJ *task_ptr)
{
RAW_SR_ALLOC();
#if (RAW_TASK_FUNCTION_CHECK > 0)
if (task_ptr == 0) {
return RAW_NULL_OBJECT;
}
#endif
if (task_ptr->priority == IDLE_PRIORITY) {
return RAW_SUSPEND_TASK_NOT_ALLOWED;
}
RAW_CRITICAL_ENTER();
if (task_ptr == raw_task_active) {
if (raw_sched_lock) {
RAW_CRITICAL_EXIT();
return RAW_SCHED_LOCKED;
}
}
switch (task_ptr->task_state) {
case RAW_RDY:
task_ptr->task_state = RAW_SUSPENDED;
remove_ready_list(&raw_ready_queue, task_ptr);
break;
case RAW_DLY:
task_ptr->task_state = RAW_DLY_SUSPENDED;
break;
case RAW_PEND:
task_ptr->task_state = RAW_PEND_SUSPENDED;
break;
case RAW_PEND_TIMEOUT:
task_ptr->task_state = RAW_PEND_TIMEOUT_SUSPENDED;
break;
case RAW_DLY_SUSPENDED:
case RAW_PEND_SUSPENDED:
case RAW_PEND_TIMEOUT_SUSPENDED:
RAW_CRITICAL_EXIT();
return RAW_SUSPENDED_AGAIN;
default:
#if (CONFIG_RAW_ASSERT > 0)
RAW_ASSERT(0);
#endif
RAW_CRITICAL_EXIT();
return RAW_STATE_UNKNOWN;
}
RAW_CRITICAL_EXIT();
raw_sched();
return RAW_SUCCESS;
}
RAW_U16 raw_task_resume(RAW_TASK_OBJ *task_ptr)
{
RAW_SR_ALLOC();
#if (RAW_TASK_FUNCTION_CHECK > 0)
if (task_ptr == 0) {
return RAW_NULL_OBJECT;
}
#endif
RAW_CRITICAL_ENTER();
switch (task_ptr->task_state) {
case RAW_RDY:
case RAW_DLY:
case RAW_PEND:
case RAW_PEND_TIMEOUT:
RAW_CRITICAL_EXIT();
return HAS_NOT_SUSPENDED;
case RAW_SUSPENDED:
task_ptr->task_state = RAW_RDY;
add_ready_list(&raw_ready_queue, task_ptr);
break;
case RAW_DLY_SUSPENDED:
task_ptr->task_state = RAW_DLY;
break;
case RAW_PEND_SUSPENDED:
task_ptr->task_state = RAW_PEND;
break;
case RAW_PEND_TIMEOUT_SUSPENDED:
task_ptr->task_state = RAW_PEND_TIMEOUT;
break;
default:
#if (CONFIG_RAW_ASSERT > 0)
RAW_ASSERT(0);
#endif
RAW_CRITICAL_EXIT();
return RAW_STATE_UNKNOWN;
}
RAW_CRITICAL_EXIT();
raw_sched();
return RAW_SUCCESS;
}
RAW_U16 raw_task_delete(RAW_TASK_OBJ *task_ptr)
{
RAW_SR_ALLOC();
#if (RAW_TASK_FUNCTION_CHECK > 0)
if (task_ptr == 0) {
return RAW_NULL_OBJECT;
}
if (raw_int_nesting) {
return RAW_NOT_CALLED_BY_ISR;
}
#endif
if (task_ptr->priority == IDLE_PRIORITY) {
return RAW_DELETE_TASK_NOT_ALLOWED;
}
RAW_CRITICAL_ENTER();
if (task_ptr == raw_task_active) {
if (raw_sched_lock) {
RAW_CRITICAL_EXIT();
return RAW_SCHED_LOCKED;
}
}
switch (task_ptr->task_state) {
case RAW_RDY:
remove_ready_list(&raw_ready_queue, task_ptr);
break;
case RAW_SUSPENDED:
break;
case RAW_DLY: /* Task is only delayed, not on any wait list */
case RAW_DLY_SUSPENDED:
tick_list_remove(task_ptr);
break;
case RAW_PEND:
case RAW_PEND_SUSPENDED:
case RAW_PEND_TIMEOUT:
case RAW_PEND_TIMEOUT_SUSPENDED:
tick_list_remove(task_ptr);
list_delete(&task_ptr->task_list);
break;
default:
#if (CONFIG_RAW_ASSERT > 0)
RAW_ASSERT(0);
#endif
RAW_CRITICAL_EXIT();
return RAW_STATE_UNKNOWN;
}
task_ptr->task_state = RAW_DELETED;
#if (RAW_TASK_STACK_CHECK > 0)
/*make after_delete_list to right position*/
after_delete_list = task_ptr->stack_check_list.next;
if (after_delete_list == &task_head) {
after_delete_list = task_head.next;
}
list_delete(&task_ptr->stack_check_list);
#endif
RAW_CRITICAL_EXIT();
raw_sched();
return RAW_SUCCESS;
}
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