内核日志缓冲区 Dmesg 实现部分代码注释

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arch/arm/arm/src/include/los_exc_pri.h

@@ -45,9 +45,9 @@ STATIC INLINE VOID OsSetCurrCpuSp(UINTPTR regSp)
     __asm__ __volatile__("mov sp, %0" :: "r"(regSp));
 }
 
-#define OS_SYSTEM_NORMAL        0
-#define OS_SYSTEM_EXC_CURR_CPU  1
-#define OS_SYSTEM_EXC_OTHER_CPU 2
+#define OS_SYSTEM_NORMAL        0	//当前CPU都处于空闲状态
+#define OS_SYSTEM_EXC_CURR_CPU  1	//当前CPU处于执行状态
+#define OS_SYSTEM_EXC_OTHER_CPU 2	//其他CPU处于执行状态
 
 extern UINT32 OsGetSystemStatus(VOID);
 extern VOID BackTraceSub(UINTPTR regFP);

arch/arm/arm/src/los_exc.c

@@ -119,8 +119,8 @@ UINT32 OsGetSystemStatus(VOID)
     UINT32 flag;
     UINT32 cpuID = g_currHandleExcCpuID;//全局变量 当前执行CPU ID
 
-    if (cpuID == INVALID_CPUID) {
-        flag = OS_SYSTEM_NORMAL;
+    if (cpuID == INVALID_CPUID) {//当前CPU处于空闲状态的情况
+        flag = OS_SYSTEM_NORMAL; 
     } else if (cpuID == ArchCurrCpuid()) {//碰到了正在执行此处代码的CPU core
         flag = OS_SYSTEM_EXC_CURR_CPU;//当前CPU
     } else {

kernel/common/los_printf.c

@@ -76,7 +76,7 @@ STATIC VOID ErrorMsg(VOID)
     const CHAR *p = "Output illegal string! vsnprintf_s failed!\n";
     UartPuts(p, (UINT32)strlen(p), UART_WITH_LOCK);
 }
-
+//串口输出,打印消息的本质就是从串口输出buf
 STATIC VOID UartOutput(const CHAR *str, UINT32 len, BOOL isLock)
 {
 #ifdef LOSCFG_SHELL_DMESG
@@ -90,7 +90,7 @@ STATIC VOID UartOutput(const CHAR *str, UINT32 len, BOOL isLock)
     UartPuts(str, len, isLock);
 #endif
 }
-
+//输出日志
 VOID OutputControl(const CHAR *str, UINT32 len, OutputType type)
 {
     switch (type) {
@@ -120,7 +120,7 @@ STATIC VOID OsVprintfFree(CHAR *buf, UINT32 bufLen)
         (VOID)LOS_MemFree(m_aucSysMem0, buf);
     }
 }
-
+//
 VOID OsVprintf(const CHAR *fmt, va_list ap, OutputType type)
 {
     INT32 len;
@@ -163,11 +163,11 @@ VOID OsVprintf(const CHAR *fmt, va_list ap, OutputType type)
     }
     *(bBuf + len) = '\0';
 
-    systemStatus = OsGetSystemStatus();
-    if ((systemStatus == OS_SYSTEM_NORMAL) || (systemStatus == OS_SYSTEM_EXC_OTHER_CPU)) {
-        OutputControl(bBuf, len, type);
-    } else if (systemStatus == OS_SYSTEM_EXC_CURR_CPU) {
-        OutputControl(bBuf, len, EXC_OUTPUT);
+    systemStatus = OsGetSystemStatus();//获取系统的状态
+    if ((systemStatus == OS_SYSTEM_NORMAL) || (systemStatus == OS_SYSTEM_EXC_OTHER_CPU)) {//当前CPU空闲或其他CPU运行时
+        OutputControl(bBuf, len, type);//
+    } else if (systemStatus == OS_SYSTEM_EXC_CURR_CPU) {//当前CPU正在执行
+        OutputControl(bBuf, len, EXC_OUTPUT);//串口以无锁的方式输出
     }
     OsVprintfFree(bBuf, bufLen);
 }

kernel/include/los_printf.h

@@ -53,19 +53,19 @@ extern VOID LOS_LkPrint(INT32 level, const CHAR *func, INT32 line, const CHAR *f
 
 #define LOS_EMG_LEVEL    0
 
-#define LOS_COMMON_LEVEL (LOS_EMG_LEVEL + 1)
+#define LOS_COMMON_LEVEL (LOS_EMG_LEVEL + 1)	//日志等级:普通
+	
+#define LOS_ERR_LEVEL    (LOS_COMMON_LEVEL + 1)	//日志等级:错误类
 
-#define LOS_ERR_LEVEL    (LOS_COMMON_LEVEL + 1)
+#define LOS_WARN_LEVEL   (LOS_ERR_LEVEL + 1)	//日志等级:警告类
 
-#define LOS_WARN_LEVEL   (LOS_ERR_LEVEL + 1)
+#define LOS_INFO_LEVEL   (LOS_WARN_LEVEL + 1)	//日志等级:信息类
 
-#define LOS_INFO_LEVEL   (LOS_WARN_LEVEL + 1)
+#define LOS_DEBUG_LEVEL  (LOS_INFO_LEVEL + 1)	//日志等级:调试类
 
-#define LOS_DEBUG_LEVEL  (LOS_INFO_LEVEL + 1)
+#define LOS_TRACE_LEVEL  (LOS_DEBUG_LEVEL + 1)	//日志等级:跟踪类
 
-#define LOS_TRACE_LEVEL  (LOS_DEBUG_LEVEL + 1)
-
-#define PRINT_LEVEL      LOS_ERR_LEVEL
+#define PRINT_LEVEL      LOS_ERR_LEVEL			//默认打印错误类
 
 typedef VOID (*pf_OUTPUT)(const CHAR *fmt, ...);
 
@@ -101,11 +101,11 @@ extern void dprintf(const char *fmt, ...);
 #define PRINT_RELEASE(fmt, args...)  LOS_LkPrint(LOS_COMMON_LEVEL, __FUNCTION__, __LINE__, fmt, ##args)
 #define PRINT_TRACE(fmt, args...)    LOS_LkPrint(LOS_TRACE_LEVEL, __FUNCTION__, __LINE__, fmt, ##args)
 
-typedef enum {
-    NO_OUTPUT = 0,
-    UART_OUTPUT = 1,
-    CONSOLE_OUTPUT = 2,
-    EXC_OUTPUT = 3
+typedef enum { //输出类型
+    NO_OUTPUT = 0,		
+    UART_OUTPUT = 1,	//串口输出
+    CONSOLE_OUTPUT = 2,	//控制台输出
+    EXC_OUTPUT = 3		//只输出当前CPU所执行任务的Log
 } OutputType;
 
 extern VOID OsVprintf(const CHAR *fmt, va_list ap, OutputType type);

shell/full/include/dmesg_pri.h

@@ -44,12 +44,12 @@ extern "C" {
 
 /*
  * The dmesg buffer is start with this info structure, then the log.
- */
+ *///dmesg缓冲区从这个信息结构开始，然后是日志内容
 typedef struct {
-    UINT32 logSize; /* The size of log in buffer */
-    UINT32 logHead; /* The index of the first log data. Data_out_flag */
-    UINT32 logTail; /* The index where to write, write in and plus one. Data_it_flag */
-    CHAR   *logBuf; /* The log buffer addr */
+    UINT32 logSize; /* The size of log in buffer */ //日志buf的大小
+    UINT32 logHead; /* The index of the first log data. Data_out_flag */ // 第一个日志数据的索引
+    UINT32 logTail; /* The index where to write, write in and plus one. Data_it_flag */ //尾部日志索引位置
+    CHAR   *logBuf; /* The log buffer addr */ //指向缓冲区开始位置
 } DmesgInfo;
 
 extern UINT32 OsDmesgInit(VOID);

shell/full/src/cmds/dmesg.c

@@ -70,14 +70,14 @@ extern "C" {
 
 #define BUF_MAX_INDEX (g_logBufSize - 1)
 
-LITE_OS_SEC_BSS STATIC SPIN_LOCK_INIT(g_dmesgSpin);
-
-STATIC DmesgInfo *g_dmesgInfo = NULL;
-STATIC UINT32 g_logBufSize = 0;
-STATIC VOID *g_mallocAddr = NULL;
-STATIC UINT32 g_dmesgLogLevel = 3;
-STATIC UINT32 g_consoleLock = 0;
-STATIC UINT32 g_uartLock = 0;
+LITE_OS_SEC_BSS STATIC SPIN_LOCK_INIT(g_dmesgSpin);//dmesg自旋锁初始化
+
+STATIC DmesgInfo *g_dmesgInfo = NULL;	//日志缓冲区描述符	
+STATIC UINT32 g_logBufSize = 0;		//日志buf大小,默认8K
+STATIC VOID *g_mallocAddr = NULL;	//dmesg buf地址
+STATIC UINT32 g_dmesgLogLevel = 3;	//默认日志等级 LOS_ERR_LEVEL = 3
+STATIC UINT32 g_consoleLock = 0;	//控制台锁
+STATIC UINT32 g_uartLock = 0;		//串口锁
 STATIC const CHAR *g_levelString[] = {
     "EMG",
     "COMMON",
@@ -107,13 +107,13 @@ STATIC VOID OsUnlockUart(VOID)
     g_uartLock = 0;
 }
 
-STATIC UINT32 OsCheckError(VOID)
+STATIC UINT32 OsCheckError(VOID)//检查缓冲区是否异常
 {
     if (g_dmesgInfo == NULL) {
         return LOS_NOK;
     }
 
-    if (g_dmesgInfo->logSize > g_logBufSize) {
+    if (g_dmesgInfo->logSize > g_logBufSize) {//超出缓冲区大小了
         return LOS_NOK;
     }
 
@@ -124,7 +124,7 @@ STATIC UINT32 OsCheckError(VOID)
 
     return LOS_OK;
 }
-
+//读取日志缓冲区数据,buf带走数据
 STATIC INT32 OsDmesgRead(CHAR *buf, UINT32 len)
 {
     UINT32 readLen;
@@ -141,17 +141,17 @@ STATIC INT32 OsDmesgRead(CHAR *buf, UINT32 len)
         return 0;
     }
 
-    readLen = len < logSize ? len : logSize;
+    readLen = len < logSize ? len : logSize;//最长只能读走g_dmesgInfo->logSize
 
-    if (head < tail) { /* Case A */
-        ret = memcpy_s(buf, len, logBuf + head, readLen);
+    if (head < tail) { /* Case A */ //不用循环的情况 head 在 tail前
+        ret = memcpy_s(buf, len, logBuf + head, readLen);//从head的位置一次性直接copy走
         if (ret != EOK) {
             return -1;
         }
-        g_dmesgInfo->logHead += readLen;
-        g_dmesgInfo->logSize -= readLen;
-    } else { /* Case B */
-        if (readLen <= (g_logBufSize - head)) {
+        g_dmesgInfo->logHead += readLen;//已占用缓冲区增加
+        g_dmesgInfo->logSize -= readLen;//可用缓冲区大小减少
+    } else { /* Case B */ 
+        if (readLen <= (g_logBufSize - head)) { 
             ret = memcpy_s(buf, len, logBuf + head, readLen);
             if (ret != EOK) {
                 return -1;
@@ -306,22 +306,22 @@ UINT32 OsCheckUartLock(VOID)
 {
     return g_uartLock;
 }
-
+//初始化内核dmesg缓存区,即内核为日志开辟的一个8K缓冲区,dmesg的管理是一个buf的循环管理.
 UINT32 OsDmesgInit(VOID)
 {
     CHAR* buffer = NULL;
 
-    buffer = (CHAR *)malloc(KERNEL_LOG_BUF_SIZE + sizeof(DmesgInfo));
+    buffer = (CHAR *)malloc(KERNEL_LOG_BUF_SIZE + sizeof(DmesgInfo));//注意这里用的是malloc分配,但鸿蒙做了适配调用了LOS_MemAlloc
     if (buffer == NULL) {
         return LOS_NOK;
     }
-    g_mallocAddr = buffer;
-    g_dmesgInfo = (DmesgInfo *)buffer;
-    g_dmesgInfo->logHead = 0;
-    g_dmesgInfo->logTail = 0;
-    g_dmesgInfo->logSize = 0;
-    g_dmesgInfo->logBuf = buffer + sizeof(DmesgInfo);
-    g_logBufSize = KERNEL_LOG_BUF_SIZE;
+    g_mallocAddr = buffer;//@note_what 取名g_mallocAddr 用于记录日志缓冲区感觉怪怪的
+    g_dmesgInfo = (DmesgInfo *)buffer;//整个buf的开头位置用于放置DmesgInfo
+    g_dmesgInfo->logHead = 0;//头部日志索引位置,注意buf中会存在很多的日志内容,每条独立
+    g_dmesgInfo->logTail = 0;//尾部日志索引位置
+    g_dmesgInfo->logSize = 0;//日志占用buf大小
+    g_dmesgInfo->logBuf = buffer + sizeof(DmesgInfo);//日志内容紧跟在DmesgInfo之后
+    g_logBufSize = KERNEL_LOG_BUF_SIZE;//buf大小 8K
 
     return LOS_OK;
 }
@@ -722,6 +722,24 @@ dmesg命令用于控制内核dmesg缓存区。
 dmesg dmesg [-c/-C/-D/-E/-L/-U]
 dmesg -s [size] dmesg -l [level dmesg > [fileA]
 
+参数说明
+
+参数	 参数说明 取值范围
+
+-c 	打印缓存区内容并清空缓存区。N/A
+
+-C 	清空缓存区。N/A
+
+-D/-E	关闭/开启控制台打印。 N/A
+
+-L/-U	关闭/开启串口打印。	N/A
+
+-s size	设置缓存区大小 size是要设置的大小。 N/A
+
+-l level	设置缓存等级。	0 - 5
+
+> fileA	将缓存区内容写入文件。N/A
+
 使用指南
 该命令依赖于LOSCFG_SHELL_DMESG，使用时通过menuconfig在配置项中开启"Enable Shell dmesg"：
 Debug ---> Enable a Debug Version ---> Enable Shell ---> Enable Shell dmesg
@@ -788,7 +806,7 @@ ERR_OUT:
     return -1;
 }
 
-SHELLCMD_ENTRY(dmesg_shellcmd, CMD_TYPE_STD, "dmesg", XARGS, (CmdCallBackFunc)OsShellCmdDmesg);//采用shell命令静态注册方式
+SHELLCMD_ENTRY(dmesg_shellcmd, CMD_TYPE_STD, "dmesg", XARGS, (CmdCallBackFunc)OsShellCmdDmesg);//shell dmesg命令 静态注册方式
 
 #ifdef __cplusplus
 #if __cplusplus

zzz/git/push.sh

 git add -A
-git commit -m  'zzz/pic 上传
+git commit -m  '内核日志缓冲区 Dmesg 实现部分代码注释
 搜索 @note_pic 可以查看全部字符图
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