开始对IPC Futex 部分代码注释,鸿蒙提供了多种IPC方式

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鸿蒙内核源码注释中文版 【 CSDN仓 | Gitee仓 | Github仓 | Coding仓 】四大仓库每日同步更新代码和wiki
项目给鸿蒙内核源码逐行加上中文注解,详细阐述框架和代码细节, 精读 HarmonyOS 内核源码, 将迅速拔高对计算机整体理解,从此高屋建瓴看问题.

kernel/base/include/los_futex_pri.h

@@ -32,7 +32,7 @@
 #ifndef _LOS_FUTEX_PRI_H
 #define _LOS_FUTEX_PRI_H
 #include "los_list.h"
-
+// Futex 是Fast Userspace muTexes的缩写 快速用户空间互斥体
 #define FUTEX_WAIT        0
 #define FUTEX_WAKE        1
 #define FUTEX_REQUEUE     3
@@ -45,13 +45,13 @@
 #define FUTEX_PRIVATE     128
 #define FUTEX_MASK        0x3U
 
-typedef struct {
-    UINTPTR      key;
-    UINT32       index;
-    UINT32       pid;
-    LOS_DL_LIST  pendList;
-    LOS_DL_LIST  queueList;
-    LOS_DL_LIST  futexList;
+typedef struct {//快锁节点
+    UINTPTR      key;	
+    UINT32       index;	
+    UINT32       pid;	//进程ID
+    LOS_DL_LIST  pendList;	//阻塞链表 阻塞任务将会挂上去
+    LOS_DL_LIST  queueList;	//队列链表
+    LOS_DL_LIST  futexList;	//快锁链表
 } FutexNode;
 
 extern UINT32 OsFutexInit(VOID);

kernel/base/include/los_task_pri.h

@@ -358,14 +358,14 @@ typedef struct {
 //typedef struct __sigset_t { unsigned long __bits[128/sizeof(long)]; } sigset_t;
 //见于 ..\vendor_hisi_hi3861_hi3861\hi3861\platform\os\Huawei_LiteOS\components\lib\libc\musl\include\bits\alltypes.h
 struct ProcessSignalInfo {//进程信号信息
-    siginfo_t *sigInfo;       /**< Signal to be dispatched */
-    LosTaskCB *defaultTcb;    /**< Default TCB */					//默认task
+    siginfo_t *sigInfo;       /**< Signal to be dispatched */		//发送信号
+    LosTaskCB *defaultTcb;    /**< Default TCB */					//默认task,指的是信号的发送方
     LosTaskCB *unblockedTcb;  /**< The signal unblock on this TCB*/	//这个task发解除阻塞信号
     LosTaskCB *awakenedTcb;   /**< This TCB was awakened */			//被唤醒task
-    LosTaskCB *receivedTcb;   /**< This TCB received the signal */	//收信号task
+    LosTaskCB *receivedTcb;   /**< This TCB received the signal */	//信号接收方task
 };
 
-typedef int (*ForEachTaskCB)(LosTaskCB *tcb, void *arg);
+typedef int (*ForEachTaskCB)(LosTaskCB *tcb, void *arg);//函数指针
 
 /**
  * @ingroup los_task

kernel/base/ipc/los_futex.c

@@ -43,9 +43,9 @@
 extern "C" {
 #endif
 #endif /* __cplusplus */
-
-#define OS_FUTEX_FROM_FUTEXLIST(ptr) LOS_DL_LIST_ENTRY(ptr, FutexNode, futexList)
-#define OS_FUTEX_FROM_QUEUELIST(ptr) LOS_DL_LIST_ENTRY(ptr, FutexNode, queueList)
+// Futex 是Fast Userspace muTexes的缩写 就是快速用户空间互斥体 ,本次注解简称它会 快锁
+#define OS_FUTEX_FROM_FUTEXLIST(ptr) LOS_DL_LIST_ENTRY(ptr, FutexNode, futexList) 	//从 futexList 位置拿节点FutexNode
+#define OS_FUTEX_FROM_QUEUELIST(ptr) LOS_DL_LIST_ENTRY(ptr, FutexNode, queueList)	//从 queueList 位置拿节点FutexNode//
 #define OS_FUTEX_KEY_BASE USER_ASPACE_BASE
 #define OS_FUTEX_KEY_MAX (USER_ASPACE_BASE + USER_ASPACE_SIZE)
 

kernel/base/ipc/los_signal.c

@@ -170,23 +170,23 @@ int OsSigprocMask(int how, const sigset_t_l *setl, sigset_t_l *oldset)
     }
     return ret;
 }
-
+//给进程的每一个task发送信号
 int OsSigProcessForeachChild(LosProcessCB *spcb, ForEachTaskCB handler, void *arg)
 {
     int ret;
 
-    /* Visit the main thread last (if present) */
-    LosTaskCB *taskCB = NULL;
+    /* Visit the main thread last (if present) */	//最后访问主线程（如果有）
+    LosTaskCB *taskCB = NULL;//遍历进程的 threadList 链表,里面存放的都是task节点
     LOS_DL_LIST_FOR_EACH_ENTRY(taskCB, &(spcb->threadSiblingList), LosTaskCB, threadList) {
-        ret = handler(taskCB, arg);
-        OS_RETURN_IF(ret != 0, ret);
+        ret = handler(taskCB, arg);//这里是个回调函数,给每个任务发信号,异步发信号
+        OS_RETURN_IF(ret != 0, ret);//这个宏的意思就是只有ret = 0时,啥也不处理.其余就返回 ret
     }
     return LOS_OK;
 }
-//信号处理函数
+//信号处理函数,这里就是上面的 handler =  SigProcessSignalHandler,见于 OsSigProcessSend
 static int SigProcessSignalHandler(LosTaskCB *tcb, void *arg)
 {
-    struct ProcessSignalInfo *info = (struct ProcessSignalInfo *)arg;
+    struct ProcessSignalInfo *info = (struct ProcessSignalInfo *)arg;//先把参数解出来
     int ret;
     int isMember;
 
@@ -195,18 +195,18 @@ static int SigProcessSignalHandler(LosTaskCB *tcb, void *arg)
     }
 
     /* If the default tcb is not setted, then set this one as default. */
-    if (!info->defaultTcb) {
+    if (!info->defaultTcb) {//如果没有默认发送方的TCB,就给一个.
         info->defaultTcb = tcb;
     }
 
     isMember = OsSigIsMember(&tcb->sig.sigwaitmask, info->sigInfo->si_signo);
-    if (isMember && (!info->awakenedTcb)) {
+    if (isMember && (!info->awakenedTcb)) {//这意味着任务正在等待此信号。
         /* This means the task is waiting for this signal. Stop looking for it and use this tcb.
          * The requirement is: if more than one task in this task group is waiting for the signal,
          * then only one indeterminate task in the group will receive the signal.
          */
-        ret = OsTcbDispatch(tcb, info->sigInfo);
-        OS_RETURN_IF(ret < 0, ret);
+        ret = OsTcbDispatch(tcb, info->sigInfo);//发送信号
+        OS_RETURN_IF(ret < 0, ret);//这种写法很有意思
 
         /* set this tcb as awakenedTcb */
         info->awakenedTcb = tcb;

zzz/git/push.sh

 git add -A
-git commit -m  '进程，task模块部分代码注释，基本完成两大模块的注释工作
+git commit -m  '开始对IPC Futex 部分代码注释,鸿蒙提供了多种IPC方式
 鸿蒙内核源码分析系列 【 CSDN | OSCHINA | WIKI 】
 鸿蒙内核源码注释中文版 【 CSDN仓 | Gitee仓 | Github仓 | Coding仓 】四大仓库每日同步更新代码和wiki
 项目给鸿蒙内核源码逐行加上中文注解,详细阐述框架和代码细节, 精读 HarmonyOS 内核源码, 将迅速拔高对计算机整体理解,从此高屋建瓴看问题.'