STM32——FreeRTOS - 任务创建和删除 ~ 动态方法
STM32——FreeRTOS - 任务创建和删除*
二、任务创建和删除（动态方法）
第10讲，还有52讲
这个就是上面的应用 初始任务删除自己 而自己处于运行态 不能立马释放自己内存 只能空闲任务执行删除 进行内存释放 但是有个问题 空闲任务什么时候到他执行？
- 在 vTaskDelete 中介绍到
动态创建任务 简介：
1.4
1.5
动态任务创建 简易调用关系：
xTaskCreate -》
-> prvInitialiseNewTask -> pxPortInitialiseStack
->prvAddNewTaskToReadyList -> prvInitialiseTaskLists -> prvAddTaskToReadyList
动态任务创建 源码细节（看中文注释）：
xTaskCreate：
#if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) BaseType_t xTaskCreate( TaskFunction_t pxTaskCode, const char * const pcName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */ const configSTACK_DEPTH_TYPE usStackDepth, void * const pvParameters, UBaseType_t uxPriority, TaskHandle_t * const pxCreatedTask ) { TCB_t * pxNewTCB; /* 任务控制块 */ BaseType_t xReturn; /* If the stack grows down then allocate the stack then the TCB so the stack * does not grow into the TCB. Likewise if the stack grows up then allocate * the TCB then the stack. */ /* 如果栈向下增长,那么先分配栈,再分配 TCB,这样栈就不会增长到 TCB 中; * 同样,如果栈向上增长,那么先分配 TCB,再分配栈. */ #if ( portSTACK_GROWTH > 0 ) /* 栈向上生长: 低地址 -> 低高地址 [STM32是向下生长] */ { /* Allocate space for the TCB. Where the memory comes from depends on * the implementation of the port malloc function and whether or not static * allocation is being used. */ pxNewTCB = ( TCB_t * ) pvPortMalloc( sizeof( TCB_t ) ); if( pxNewTCB != NULL ) { /* Allocate space for the stack used by the task being created. * The base of the stack memory stored in the TCB so the task can * be deleted later if required. */ pxNewTCB->pxStack = ( StackType_t * ) pvPortMallocStack( ( ( ( size_t ) usStackDepth ) * sizeof( StackType_t ) ) ); /*lint !e961 MISRA exception as the casts are only redundant for some ports. */ if( pxNewTCB->pxStack == NULL ) { /* Could not allocate the stack. Delete the allocated TCB. */ vPortFree( pxNewTCB ); pxNewTCB = NULL; } } } #else /* portSTACK_GROWTH */ /* 栈向下生长: 高地址 -> 低地址 [STM32就是向下生长] */ { StackType_t * pxStack; //任务堆栈，用来存放首地址 /* 为正在创建的任务所使用的栈分配空间。调用malloc函数由系统自动分配堆空间:长度*字节*/ pxStack = pvPortMallocStack( ( ( ( size_t ) usStackDepth ) * sizeof( StackType_t ) ) ); /*lint !e9079 All values returned by pvPortMalloc() have at least the alignment required by the MCU's stack and this allocation is the stack. */ if( pxStack != NULL ) { /* 为任务控制块分配空间 (TCB). */ pxNewTCB = ( TCB_t * ) pvPortMalloc( sizeof( TCB_t ) ); /*lint !e9087 !e9079 All values returned by pvPortMalloc() have at least the alignment required by the MCU's stack, and the first member of TCB_t is always a pointer to the task's stack. */ if( pxNewTCB != NULL ) { /* 将任务控制块首地址存储. */ pxNewTCB->pxStack = pxStack; } else { /* 该栈无法使用，因为TCB组件尚未创建。再把它释放掉。 */ vPortFreeStack( pxStack ); } } else { pxNewTCB = NULL; } } #endif /* portSTACK_GROWTH */ if( pxNewTCB != NULL ) { // 条件编译不管 #if ( tskSTATIC_AND_DYNAMIC_ALLOCATION_POSSIBLE != 0 ) /*lint !e9029 !e731 Macro has been consolidated for readability reasons. */ { /* Tasks can be created statically or dynamically, so note this * task was created dynamically in case it is later deleted. */ pxNewTCB->ucStaticallyAllocated = tskDYNAMICALLY_ALLOCATED_STACK_AND_TCB; } #endif /* tskSTATIC_AND_DYNAMIC_ALLOCATION_POSSIBLE */ /* 初始化任务控制块 TCB 中的其余成员 (除了pxNewTCB->pxStack) */ prvInitialiseNewTask( pxTaskCode, pcName, ( uint32_t ) usStackDepth, pvParameters, uxPriority, pxCreatedTask, pxNewTCB, NULL ); /* 添加新创建的任务到 就绪列表 中 */ prvAddNewTaskToReadyList( pxNewTCB ); xReturn = pdPASS; } else { xReturn = errCOULD_NOT_ALLOCATE_REQUIRED_MEMORY; } return xReturn; } #endif /* configSUPPORT_DYNAMIC_ALLOCATION */ /*-----------------------------------------------------------*/prvInitialiseNewTask
static void prvInitialiseNewTask( TaskFunction_t pxTaskCode, const char * const pcName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */ const uint32_t ulStackDepth, void * const pvParameters, UBaseType_t uxPriority, TaskHandle_t * const pxCreatedTask, TCB_t * pxNewTCB, const MemoryRegion_t * const xRegions ) { StackType_t * pxTopOfStack; UBaseType_t x; /* MPU 内存保护功能 是否开启的判断宏. */ #if ( portUSING_MPU_WRAPPERS == 1 ) /* Should the task be created in privileged mode? */ BaseType_t xRunPrivileged