因同步官方代码,导致调度过程部分需重新加注.调度部分目前代码结构很清晰,将调度和进程,任务彻底剥离开.

    百万汉字注解 + 百篇博客分析 => 挖透鸿蒙内核源码
    国内:https://weharmony.21cloudbox.com
    国外:https://weharmony.github.io

kernel/base/include/los_process_pri.h

@@ -78,7 +78,7 @@ typedef struct ProcessCB {
     CHAR                 processName[OS_PCB_NAME_LEN]; /**< Process name */	//进程名称
     UINT32               processID;                    /**< process ID = leader thread ID */	//进程ID,由进程池分配,范围[0,64]
     UINT16               processStatus;                /**< [15:4] process Status; [3:0] The number of threads currently
-                                                            running in the process *///这里设计很巧妙.用一个变量表示了两层逻辑 数量和状态,点赞!
+                                                            running in the process *///这里设计很巧妙.用一个变量表示了两层逻辑 数量和状态,点赞!从这里也可以看出一个进程可以有多个正在运行的任务
     UINT16               priority;                     /**< process priority */	//进程优先级
     UINT16               consoleID;                    /**< The console id of task belongs  *///任务的控制台id归属
     UINT16               processMode;                  /**< Kernel Mode:0; User Mode:1; */	//模式指定为内核还是用户进程

kernel/base/include/los_sched_pri.h

@@ -49,14 +49,14 @@ extern UINT32 g_taskScheduled;
 typedef BOOL (*SchedScan)(VOID);
 
 extern UINT64 g_sysSchedStartTime;
-
+//获取当前调度经历了多少个时间周期
 STATIC INLINE UINT64 OsGerCurrSchedTimeCycle(VOID)
 {
     if (g_sysSchedStartTime == 0) {
         return g_sysSchedStartTime;
     }
 
-    return (HalClockGetCycles() - g_sysSchedStartTime);
+    return (HalClockGetCycles() - g_sysSchedStartTime);//经历周期数
 }
 
 STATIC INLINE VOID OsSchedIrqUpdateUsedTime(VOID)

kernel/base/include/los_sortlink_pri.h

@@ -42,16 +42,16 @@ extern "C" {
 #endif /* __cplusplus */
 #endif /* __cplusplus */
 
-typedef enum {
-    OS_SORT_LINK_TASK = 1,
-    OS_SORT_LINK_SWTMR = 2,
+typedef enum {//因为任务和定时器都是吃CPU的,让CPU不停工作的主要就是这两宝贝.
+    OS_SORT_LINK_TASK = 1,	//任务排序
+    OS_SORT_LINK_SWTMR = 2,	//定时器排序
 } SortLinkType;
 
 typedef struct {
-    LOS_DL_LIST sortLinkNode;
-    UINT64      responseTime;
+    LOS_DL_LIST sortLinkNode;//任务排序链表,注意上面挂的是一个个等待的任务
+    UINT64      responseTime;//响应时间
 #if (LOSCFG_KERNEL_SMP == YES)
-    UINT32      cpuid;
+    UINT32      cpuid;//需要哪个CPU处理
 #endif
 } SortLinkList;
 

kernel/base/include/los_task_pri.h

@@ -313,13 +313,13 @@ typedef struct {
     UINT16          taskStatus;         /**< Task status */			//各种状态标签，可以拥有多种标签，按位标识
     UINT16          priority;           /**< Task priority */		//任务优先级[0:31],默认是31级
     UINT16          policy;				//任务的调度方式(三种 .. LOS_SCHED_RR )
-    UINT64          startTime;          /**< The start time of each phase of task */
-    UINT64          irqStartTime;       /**< Interrupt start time */
-    UINT32          irqUsedTime;        /**< Interrupt consumption time */
-    UINT32          initTimeSlice;      /**< Task init time slice */
-    INT32           timeSlice;          /**< Task remaining time slice */
-    UINT32          waitTimes;          /**< Task delay time, tick number */
-    SortLinkList    sortList;           /**< Task sortlink node */
+    UINT64          startTime;          /**< The start time of each phase of task *///任务开始时间
+    UINT64          irqStartTime;       /**< Interrupt start time *///任务中断开始时间
+    UINT32          irqUsedTime;        /**< Interrupt consumption time *///任务中断恢复时间
+    UINT32          initTimeSlice;      /**< Task init time slice *///任务初始的时间片
+    INT32           timeSlice;          /**< Task remaining time slice *///任务剩余时间片
+    UINT32          waitTimes;          /**< Task delay time, tick number *///设置任务调度延期时间
+    SortLinkList    sortList;           /**< Task sortlink node */	//任务排序链表节点
     UINT32          stackSize;          /**< Task stack size */		//内核态栈大小,内存来自内核空间
     UINTPTR         topOfStack;         /**< Task stack top */		//内核态栈顶 bottom = top + size
     UINT32          taskID;             /**< Task ID */				//任务ID，任务池本质是一个大数组，ID就是数组的索引，默认 < 128

kernel/base/sched/sched_sq/los_sched.c

@@ -76,7 +76,7 @@ typedef struct {//调度器
 
 STATIC Sched *g_sched = NULL;//全局调度器
 STATIC UINT64 g_schedTickMaxResponseTime;
-UINT64 g_sysSchedStartTime = 0;
+UINT64 g_sysSchedStartTime = 0;//系统调度开始时间,这个时间指的是周期
 
 #ifdef LOSCFG_SCHED_TICK_DEBUG
 #define OS_SCHED_DEBUG_DATA_NUM  1000
@@ -249,14 +249,14 @@ UINT32 OsSchedSetTickTimerType(UINT32 timerType)
 
     return LOS_OK;
 }
-
+//设置调度开始时间
 STATIC VOID OsSchedSetStartTime(UINT64 currCycle)
 {
-    if (g_sysSchedStartTime == 0) {
+    if (g_sysSchedStartTime == 0) {//说明只能设置一次.
         g_sysSchedStartTime = currCycle;
     }
 }
-
+//升级时间片
 STATIC INLINE VOID OsTimeSliceUpdate(LosTaskCB *taskCB, UINT64 currTime)
 {
     LOS_ASSERT(currTime >= taskCB->startTime);
@@ -464,12 +464,12 @@ STATIC INLINE VOID OsSchedWakePendTimeTask(UINT64 currTime, LosTaskCB *taskCB, B
 
     LOS_SpinUnlock(&g_taskSpin);
 }
-
+//扫描那些处于等待状态的任务是否时间到了
 STATIC INLINE BOOL OsSchedScanTimerList(VOID)
 {
     Percpu *cpu = OsPercpuGet();
     BOOL needSchedule = FALSE;
-    SortLinkAttribute *taskSortLink = &OsPercpuGet()->taskSortLink;
+    SortLinkAttribute *taskSortLink = &OsPercpuGet()->taskSortLink;//获取本CPU核上挂的所有等待的任务排序链表
     LOS_DL_LIST *listObject = &taskSortLink->sortLink;
     /*
      * When task is pended with timeout, the task block is on the timeout sortlink
@@ -486,9 +486,9 @@ STATIC INLINE BOOL OsSchedScanTimerList(VOID)
         return needSchedule;
     }
 
-    SortLinkList *sortList = LOS_DL_LIST_ENTRY(listObject->pstNext, SortLinkList, sortLinkNode);
-    UINT64 currTime = OsGerCurrSchedTimeCycle();
-    while (sortList->responseTime <= currTime) {
+    SortLinkList *sortList = LOS_DL_LIST_ENTRY(listObject->pstNext, SortLinkList, sortLinkNode);//获取每个优先级上的任务链表头节点
+    UINT64 currTime = OsGerCurrSchedTimeCycle();//获取当前时钟周期
+    while (sortList->responseTime <= currTime) {//
         LosTaskCB *taskCB = LOS_DL_LIST_ENTRY(sortList, LosTaskCB, sortList);
         OsDeleteNodeSortLink(taskSortLink, &taskCB->sortList);
         LOS_SpinUnlock(&cpu->taskSortLinkSpin);
@@ -617,42 +617,42 @@ VOID OsSchedTaskExit(LosTaskCB *taskCB)
         taskCB->taskStatus &= ~(OS_TASK_STATUS_DELAY | OS_TASK_STATUS_PEND_TIME);
     }
 }
-
+//通过本函数可以看出 yield 的真正含义是主动让出CPU,当它自己还是在就绪队列中,跑末位去排队了.像个活雷锋.
 VOID OsSchedYield(VOID)
 {
     LosTaskCB *runTask = OsCurrTaskGet();
 
-    runTask->timeSlice = 0;
+    runTask->timeSlice = 0;//时间片变成0,代表主动让出运行时间.
 
-    runTask->startTime = OsGerCurrSchedTimeCycle();
-    OsSchedTaskEnQueue(runTask);
-    OsSchedResched();
+    runTask->startTime = OsGerCurrSchedTimeCycle();//重新设置任务开始周期
+    OsSchedTaskEnQueue(runTask);//跑队列尾部排队
+    OsSchedResched();//发起调度
 }
-
+//延期调度
 VOID OsSchedDelay(LosTaskCB *runTask, UINT32 tick)
 {
-    OsSchedTaskDeQueue(runTask);
-    runTask->taskStatus |= OS_TASK_STATUS_DELAY;
-    runTask->waitTimes = tick;
+    OsSchedTaskDeQueue(runTask);//将任务从就绪队列中删除
+    runTask->taskStatus |= OS_TASK_STATUS_DELAY;//任务状态改成延期
+    runTask->waitTimes = tick;//延期节拍数
 
-    OsSchedResched();
+    OsSchedResched();//既然本任务延期,就需要发起新的调度.
 }
-
+//任务进入等待链表
 UINT32 OsSchedTaskWait(LOS_DL_LIST *list, UINT32 ticks, BOOL needSched)
 {
-    LosTaskCB *runTask = OsCurrTaskGet();
-    OsSchedTaskDeQueue(runTask);
+    LosTaskCB *runTask = OsCurrTaskGet();//获取当前任务
+    OsSchedTaskDeQueue(runTask);//将任务从就绪队列中删除
 
-    runTask->taskStatus |= OS_TASK_STATUS_PENDING;
-    LOS_ListTailInsert(list, &runTask->pendList);
+    runTask->taskStatus |= OS_TASK_STATUS_PENDING;//任务状态改成阻塞
+    LOS_ListTailInsert(list, &runTask->pendList);//挂入阻塞链表
 
-    if (ticks != LOS_WAIT_FOREVER) {
-        runTask->taskStatus |= OS_TASK_STATUS_PEND_TIME;
-        runTask->waitTimes = ticks;
+    if (ticks != LOS_WAIT_FOREVER) {//如果不是永久的等待
+        runTask->taskStatus |= OS_TASK_STATUS_PEND_TIME;//标记为有时间的阻塞
+        runTask->waitTimes = ticks;//要阻塞多久
     }
 
-    if (needSched == TRUE) {
-        OsSchedResched();
+    if (needSched == TRUE) {//是否需要调度
+        OsSchedResched();//申请调度,将切换任务上下文
         if (runTask->taskStatus & OS_TASK_STATUS_TIMEOUT) {
             runTask->taskStatus &= ~OS_TASK_STATUS_TIMEOUT;
             return LOS_ERRNO_TSK_TIMEOUT;
@@ -661,7 +661,7 @@ UINT32 OsSchedTaskWait(LOS_DL_LIST *list, UINT32 ticks, BOOL needSched)
 
     return LOS_OK;
 }
-
+//任务从等待链表中恢复,并从链表中摘除.
 VOID OsSchedTaskWake(LosTaskCB *resumedTask)
 {
     LOS_ListDelete(&resumedTask->pendList);
@@ -707,7 +707,7 @@ BOOL OsSchedModifyTaskSchedParam(LosTaskCB *taskCB, UINT16 policy, UINT16 priori
 
     return FALSE;
 }
-
+//修改进程调度参数
 BOOL OsSchedModifyProcessSchedParam(LosProcessCB *processCB, UINT16 policy, UINT16 priority)
 {
     LosTaskCB *taskCB = NULL;
@@ -802,7 +802,7 @@ UINT32 OsSchedInit(VOID)
         LOS_SpinInit(&cpu->swtmrSortLinkSpin);//操作具体CPU核定时器排序链表
     }
 
-    g_sched->taskScan = OsSchedScanTimerList;//
+    g_sched->taskScan = OsSchedScanTimerList;//扫描那些处于等待状态的任务是否时间到了
 
 #ifdef LOSCFG_SCHED_TICK_DEBUG
     ret = OsSchedDebugInit();
@@ -849,32 +849,32 @@ FIND_TASK:
     OsSchedDeTaskQueue(newTask, OS_PCB_FROM_PID(newTask->processID));
     return newTask;
 }
-//开始调度,每个CPU核都会执行这个函数一次.
+//CPU的调度开始,每个CPU核都会执行这个函数一次.
 VOID OsSchedStart(VOID)
 {
-    UINT32 cpuid = ArchCurrCpuid();
+    UINT32 cpuid = ArchCurrCpuid();//从系统寄存器上获取当前执行的CPU核编号
     UINT32 intSave;
 
     SCHEDULER_LOCK(intSave);
 
-    OsTickStart();
+    OsTickStart();//开始了属于本核的tick 
 
-    LosTaskCB *newTask = OsGetTopTask();
-    LosProcessCB *newProcess = OS_PCB_FROM_PID(newTask->processID);
+    LosTaskCB *newTask = OsGetTopTask();//拿一个优先级最高的任务
+    LosProcessCB *newProcess = OS_PCB_FROM_PID(newTask->processID);//获取该任务的进程实体
 
-    newTask->taskStatus |= OS_TASK_STATUS_RUNNING;
+    newTask->taskStatus |= OS_TASK_STATUS_RUNNING;//变成运行状态,注意此时该任务还没真正的运行
     newProcess->processStatus |= OS_PROCESS_STATUS_RUNNING;
-    newProcess->processStatus = OS_PROCESS_RUNTASK_COUNT_ADD(newProcess->processStatus);
+    newProcess->processStatus = OS_PROCESS_RUNTASK_COUNT_ADD(newProcess->processStatus);//当前任务的数量也增加一个
 
-    OsSchedSetStartTime(HalClockGetCycles());
+    OsSchedSetStartTime(HalClockGetCycles());//设置调度开始时间
     newTask->startTime = OsGerCurrSchedTimeCycle();
 
-#if (LOSCFG_KERNEL_SMP == YES)
+#if (LOSCFG_KERNEL_SMP == YES)//注意：需要设置当前cpu，以防第一个任务删除可能会失败，因为此标志与实际当前 cpu 不匹配。
     /*
      * attention: current cpu needs to be set, in case first task deletion
      * may fail because this flag mismatch with the real current cpu.
      */
-    newTask->currCpu = cpuid;
+    newTask->currCpu = cpuid;//设置当前CPU,确保第一个任务由本CPU核执行
 #endif
 
     OsCurrTaskSet((VOID *)newTask);

zzz/git/push.sh

 git add -A
-git commit -m  '对mtd,disk,filemap注解 
+git commit -m  '因同步官方代码,导致调度过程部分需重新加注.调度部分目前代码结构很清晰,将调度和进程,任务彻底剥离开. 
     百万汉字注解 + 百篇博客分析 => 挖透鸿蒙内核源码
     国内:https://weharmony.21cloudbox.com
     国外:https://weharmony.github.io