完善进程部分注释,注释进程是怎么一步步被Fork的

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.

README.md

@@ -6,7 +6,7 @@
 
 # **[kernel\_liteos\_a_note](https://gitee.com/weharmony/kernel_liteos_a_note): 鸿蒙内核源码注释中文版**
 
-[![star](https://gitee.com/weharmony/kernel_liteos_a_note/badge/star.svg?theme=dark)](https://gitee.com/weharmony/kernel_liteos_a_note)[![下载源码](https://gitee.com/oschina/git-osc/widgets/widget_3.svg)](https://gitee.com/weharmony/kernel_liteos_a_note)[![fork](https://gitee.com/weharmony/kernel_liteos_a_note/badge/fork.svg?theme=dark)](https://gitee.com/weharmony/kernel_liteos_a_note)
+[![star](https://gitee.com/weharmony/kernel_liteos_a_note/badge/star.svg?theme=dark)](https://gitee.com/weharmony/kernel_liteos_a_note)[![fork](https://gitee.com/weharmony/kernel_liteos_a_note/badge/fork.svg?theme=dark)](https://gitee.com/weharmony/kernel_liteos_a_note)
 
 每个码农,职业生涯,都应精读一遍内核源码. 鸿蒙内核源码就是很好的精读项目.一旦熟悉内核代码级实现,将迅速拔高对计算机整体理解,从此高屋建瓴看问题.
 

arch/arm/arm/include/los_arch_mmu.h

@@ -48,8 +48,8 @@ extern "C" {
 
 typedef struct ArchMmu {
     LosMux              mtx;            /**< arch mmu page table entry modification mutex lock */
-    VADDR_T             *virtTtb;       /**< translation table base virtual addr */
-    PADDR_T             physTtb;        /**< translation table base phys addr */
+    VADDR_T             *virtTtb;       /**< translation table base virtual addr */ //注意:这里是个指针,内核操作都用这个地址
+    PADDR_T             physTtb;        /**< translation table base phys addr */	//注意:这里是个值,这个值是记录给MMU使用的,MMU只认它,内核是无法使用的
     UINT32              asid;           /**< TLB asid */
     LOS_DL_LIST         ptList;         /**< page table vm page list *///L1 为表头，后面挂的是n多L2
 } LosArchMmu;

arch/arm/arm/src/los_hw.c

@@ -124,8 +124,8 @@ LITE_OS_SEC_TEXT VOID OsUserCloneParentStack(LosTaskCB *childTaskCB, LosTaskCB *
 	//cloneStack指向 TaskContext
     LOS_ASSERT(parentTaskCB->taskStatus & OS_TASK_STATUS_RUNNING);//当前任务一定是正在运行的task
 
-    (VOID)memcpy_s(childTaskCB->stackPointer, sizeof(TaskContext), cloneStack, sizeof(TaskContext));
-    context->R[0] = 0;
+    (VOID)memcpy_s(childTaskCB->stackPointer, sizeof(TaskContext), cloneStack, sizeof(TaskContext));//直接把任务上下文拷贝了一份
+    context->R[0] = 0;//R0寄存器为0
 }
 //用户任务使用栈初始化
 LITE_OS_SEC_TEXT_INIT VOID OsUserTaskStackInit(TaskContext *context, TSK_ENTRY_FUNC taskEntry, UINTPTR stack)

kernel/base/core/los_process.c

@@ -1736,11 +1736,11 @@ STATIC UINT32 OsCopyTask(UINT32 flags, LosProcessCB *childProcessCB, const CHAR
 
     if (OsProcessIsUserMode(childProcessCB)) {//是否是用户进程
         SCHEDULER_LOCK(intSave);
-        OsUserCloneParentStack(childTaskCB, OsCurrTaskGet());
+        OsUserCloneParentStack(childTaskCB, OsCurrTaskGet());//任务栈拷贝
         SCHEDULER_UNLOCK(intSave);
     }
-    OS_TASK_PRI_QUEUE_ENQUEUE(childProcessCB, childTaskCB);
-    childTaskCB->taskStatus |= OS_TASK_STATUS_READY;
+    OS_TASK_PRI_QUEUE_ENQUEUE(childProcessCB, childTaskCB);//将task加入进程的就绪队列
+    childTaskCB->taskStatus |= OS_TASK_STATUS_READY;//任务状态贴上就绪标签
     return LOS_OK;
 }
 //拷贝父亲大人的遗传基因信息
@@ -1782,10 +1782,10 @@ STATIC UINT32 OsCopyMM(UINT32 flags, LosProcessCB *childProcessCB, LosProcessCB
         return LOS_OK;
     }
 
-    if (flags & CLONE_VM) {
+    if (flags & CLONE_VM) {//贴有虚拟内存的标签
         SCHEDULER_LOCK(intSave);
-        childProcessCB->vmSpace->archMmu.virtTtb = runProcessCB->vmSpace->archMmu.virtTtb;
-        childProcessCB->vmSpace->archMmu.physTtb = runProcessCB->vmSpace->archMmu.physTtb;
+        childProcessCB->vmSpace->archMmu.virtTtb = runProcessCB->vmSpace->archMmu.virtTtb;//TTB虚拟地址基地址,即L1表存放位置,virtTtb是个指针,进程的虚拟空间是指定的范围的
+        childProcessCB->vmSpace->archMmu.physTtb = runProcessCB->vmSpace->archMmu.physTtb;//TTB物理地址基地址,physTtb是个值,取决于运行时映射到物理内存的具体哪个位置.
         SCHEDULER_UNLOCK(intSave);
         return LOS_OK;
     }
@@ -1796,7 +1796,7 @@ STATIC UINT32 OsCopyMM(UINT32 flags, LosProcessCB *childProcessCB, LosProcessCB
     }
     return LOS_OK;
 }
-
+//拷贝文件信息
 STATIC UINT32 OsCopyFile(UINT32 flags, LosProcessCB *childProcessCB, LosProcessCB *runProcessCB)
 {
 #ifdef LOSCFG_FS_VFS
@@ -1832,7 +1832,7 @@ STATIC UINT32 OsForkInitPCB(UINT32 flags, LosProcessCB *child, const CHAR *name,
 
     return OsCopyTask(flags, child, name, sp, size);//拷贝任务，设置任务入口函数，栈大小
 }
-
+//设置进程组和加入进程调度就绪队列
 STATIC UINT32 OsChildSetProcessGroupAndSched(LosProcessCB *child, LosProcessCB *run)
 {
     UINT32 intSave;
@@ -1840,17 +1840,17 @@ STATIC UINT32 OsChildSetProcessGroupAndSched(LosProcessCB *child, LosProcessCB *
     ProcessGroup *group = NULL;
 
     SCHEDULER_LOCK(intSave);
-    if (run->group->groupID == OS_USER_PRIVILEGE_PROCESS_GROUP) {
-        ret = OsSetProcessGroupIDUnsafe(child->processID, child->processID, &group);
+    if (run->group->groupID == OS_USER_PRIVILEGE_PROCESS_GROUP) {//如果是有用户特权进程组
+        ret = OsSetProcessGroupIDUnsafe(child->processID, child->processID, &group);//设置组ID,存在不安全的风险
         if (ret != LOS_OK) {
             SCHEDULER_UNLOCK(intSave);
             return LOS_ENOMEM;
         }
     }
 
-    OS_PROCESS_PRI_QUEUE_ENQUEUE(child);
-    child->processStatus &= ~OS_PROCESS_STATUS_INIT;
-    child->processStatus |= OS_PROCESS_STATUS_READY;
+    OS_PROCESS_PRI_QUEUE_ENQUEUE(child);//
+    child->processStatus &= ~OS_PROCESS_STATUS_INIT;//去掉初始化标签
+    child->processStatus |= OS_PROCESS_STATUS_READY;//贴上就绪标签
 
 #ifdef LOSCFG_KERNEL_CPUP
     OsCpupSet(child->processID);
@@ -1865,19 +1865,19 @@ STATIC INT32 OsCopyProcessResources(UINT32 flags, LosProcessCB *child, LosProces
 {
     UINT32 ret;
 
-    ret = OsCopyMM(flags, child, run);
+    ret = OsCopyMM(flags, child, run);//拷贝虚拟空间
     if (ret != LOS_OK) {
         return ret;
     }
 
-    ret = OsCopyFile(flags, child, run);
+    ret = OsCopyFile(flags, child, run);//拷贝文件信息
     if (ret != LOS_OK) {
         return ret;
     }
 
 #if (LOSCFG_KERNEL_LITEIPC == YES)
-    if (OsProcessIsUserMode(child)) {
-        ret = LiteIpcPoolReInit(&child->ipcInfo, (const ProcIpcInfo *)(&run->ipcInfo));
+    if (OsProcessIsUserMode(child)) {//用户模式下
+        ret = LiteIpcPoolReInit(&child->ipcInfo, (const ProcIpcInfo *)(&run->ipcInfo));//重新初始化IPC池
         if (ret != LOS_OK) {
             return LOS_ENOMEM;
         }
@@ -1885,7 +1885,7 @@ STATIC INT32 OsCopyProcessResources(UINT32 flags, LosProcessCB *child, LosProces
 #endif
 
 #ifdef LOSCFG_SECURITY_CAPABILITY
-    OsCopyCapability(run, child);
+    OsCopyCapability(run, child);//拷贝安全能力
 #endif
 
     return LOS_OK;
@@ -1907,18 +1907,18 @@ STATIC INT32 OsCopyProcess(UINT32 flags, const CHAR *name, UINTPTR sp, UINT32 si
         goto ERROR_INIT;
     }
 
-    ret = OsCopyProcessResources(flags, child, run);
+    ret = OsCopyProcessResources(flags, child, run);//拷贝进程的资源,包括虚拟空间,文件,安全,IPC ==
     if (ret != LOS_OK) {
         goto ERROR_TASK;
     }
 
-    ret = OsChildSetProcessGroupAndSched(child, run);
+    ret = OsChildSetProcessGroupAndSched(child, run);//设置进程组和加入进程调度就绪队列
     if (ret != LOS_OK) {
         goto ERROR_TASK;
     }
 
-    LOS_MpSchedule(OS_MP_CPU_ALL);
-    if (OS_SCHEDULER_ACTIVE) {
+    LOS_MpSchedule(OS_MP_CPU_ALL);//给各CPU发送准备接受调度信号
+    if (OS_SCHEDULER_ACTIVE) {//当前CPU core处于活动状态
         LOS_Schedule();// 申请调度
     }
 

kernel/base/vm/los_vm_map.c

@@ -255,49 +255,49 @@ STATUS_T LOS_VmSpaceClone(LosVmSpace *oldVmSpace, LosVmSpace *newVmSpace)
         return LOS_ERRNO_VM_INVALID_ARGS;
     }
 
-    if ((OsIsVmRegionEmpty(oldVmSpace) == TRUE) || (oldVmSpace == &g_kVmSpace)) {
+    if ((OsIsVmRegionEmpty(oldVmSpace) == TRUE) || (oldVmSpace == &g_kVmSpace)) {//不允许clone内核空间,内核空间是独一无二的.
         return LOS_ERRNO_VM_INVALID_ARGS;
     }
-
+	//空间克隆的主体实现是:线性区重新一个个分配物理内存,重新映射.
     /* search the region list */
     newVmSpace->mapBase = oldVmSpace->mapBase;
     newVmSpace->heapBase = oldVmSpace->heapBase;
     newVmSpace->heapNow = oldVmSpace->heapNow;
     (VOID)LOS_MuxAcquire(&oldVmSpace->regionMux);
-    RB_SCAN_SAFE(&oldVmSpace->regionRbTree, pstRbNode, pstRbNodeNext)
+    RB_SCAN_SAFE(&oldVmSpace->regionRbTree, pstRbNode, pstRbNodeNext)//红黑树循环开始
         oldRegion = (LosVmMapRegion *)pstRbNode;
-        newRegion = OsVmRegionDup(newVmSpace, oldRegion, oldRegion->range.base, oldRegion->range.size);
+        newRegion = OsVmRegionDup(newVmSpace, oldRegion, oldRegion->range.base, oldRegion->range.size);//复制线性区
         if (newRegion == NULL) {
             VM_ERR("dup new region failed");
             ret = LOS_ERRNO_VM_NO_MEMORY;
             goto ERR_CLONE_ASPACE;
         }
 
-        if (oldRegion->regionFlags & VM_MAP_REGION_FLAG_SHM) {
-            OsShmFork(newVmSpace, oldRegion, newRegion);
-            continue;
+        if (oldRegion->regionFlags & VM_MAP_REGION_FLAG_SHM) {//如果老线性区是共享内存
+            OsShmFork(newVmSpace, oldRegion, newRegion);//fork共享线性区,如此新虚拟空间也能用那个线性区
+            continue;//不往下走了,因为共享内存不需要重新映射,下面无非就是需要MMU映射虚拟地址<-->物理地址
         }
 
-        if (oldRegion == oldVmSpace->heap) {
-            newVmSpace->heap = newRegion;
+        if (oldRegion == oldVmSpace->heap) {//如果这个线性区是堆区
+            newVmSpace->heap = newRegion;//那么新的线性区也是新虚拟空间的堆区
         }
 
-        numPages = newRegion->range.size >> PAGE_SHIFT;
-        for (i = 0; i < numPages; i++) {
+        numPages = newRegion->range.size >> PAGE_SHIFT;//计算线性区页数
+        for (i = 0; i < numPages; i++) {//一页一页进行重新映射
             vaddr = newRegion->range.base + (i << PAGE_SHIFT);
-            if (LOS_ArchMmuQuery(&oldVmSpace->archMmu, vaddr, &paddr, &flags) != LOS_OK) {
+            if (LOS_ArchMmuQuery(&oldVmSpace->archMmu, vaddr, &paddr, &flags) != LOS_OK) {//先查物理地址
                 continue;
             }
 
-            page = LOS_VmPageGet(paddr);
+            page = LOS_VmPageGet(paddr);//通过物理页获取物理内存的页框
             if (page != NULL) {
                 LOS_AtomicInc(&page->refCounts);//refCounts 自增
             }
-            if (flags & VM_MAP_REGION_FLAG_PERM_WRITE) {
-                LOS_ArchMmuUnmap(&oldVmSpace->archMmu, vaddr, 1);
-                LOS_ArchMmuMap(&oldVmSpace->archMmu, vaddr, paddr, 1, flags & ~VM_MAP_REGION_FLAG_PERM_WRITE);
+            if (flags & VM_MAP_REGION_FLAG_PERM_WRITE) {//可写入区标签
+                LOS_ArchMmuUnmap(&oldVmSpace->archMmu, vaddr, 1);//取消老空间映射
+                LOS_ArchMmuMap(&oldVmSpace->archMmu, vaddr, paddr, 1, flags & ~VM_MAP_REGION_FLAG_PERM_WRITE);//老空间重新映射
             }
-            LOS_ArchMmuMap(&newVmSpace->archMmu, vaddr, paddr, 1, flags & ~VM_MAP_REGION_FLAG_PERM_WRITE);
+            LOS_ArchMmuMap(&newVmSpace->archMmu, vaddr, paddr, 1, flags & ~VM_MAP_REGION_FLAG_PERM_WRITE);//映射新空间
 
 #ifdef LOSCFG_FS_VFS
             if (LOS_IsRegionFileValid(oldRegion)) {
@@ -311,7 +311,7 @@ STATUS_T LOS_VmSpaceClone(LosVmSpace *oldVmSpace, LosVmSpace *newVmSpace)
             }
 #endif
         }
-    RB_SCAN_SAFE_END(&oldVmSpace->regionRbTree, pstRbNode, pstRbNodeNext)
+    RB_SCAN_SAFE_END(&oldVmSpace->regionRbTree, pstRbNode, pstRbNodeNext)//红黑树循环结束
     goto OUT_CLONE_ASPACE;
 ERR_CLONE_ASPACE:
     if (LOS_VmSpaceFree(newVmSpace) != LOS_OK) {

kernel/base/vm/shm.c

@@ -319,37 +319,37 @@ VOID OsShmFork(LosVmSpace *space, LosVmMapRegion *oldRegion, LosVmMapRegion *new
         return;
     }
 
-    newRegion->shmid = oldRegion->shmid;
-    newRegion->forkFlags = oldRegion->forkFlags;
-    ShmVmmMapping(space, &seg->node, newRegion->range.base, newRegion->regionFlags);
-    seg->ds.shm_nattch++;
+    newRegion->shmid = oldRegion->shmid;//一样的共享区ID
+    newRegion->forkFlags = oldRegion->forkFlags;//forkFlags也一样了
+    ShmVmmMapping(space, &seg->node, newRegion->range.base, newRegion->regionFlags);//共享内存映射
+    seg->ds.shm_nattch++;//附在共享线性区上的进程数++
     SYSV_SHM_UNLOCK();
 }
-
+//释放共享线性区
 VOID OsShmRegionFree(LosVmSpace *space, LosVmMapRegion *region)
 {
     struct shmIDSource *seg = NULL;
 
     SYSV_SHM_LOCK();
-    seg = ShmFindSeg(region->shmid);
+    seg = ShmFindSeg(region->shmid);////通过线性区ID获取对应的共享资源ID结构体
     if (seg == NULL) {
         SYSV_SHM_UNLOCK();
         return;
     }
 
-    ShmPagesRefDec(seg);
-    seg->ds.shm_nattch--;
-    if (seg->ds.shm_nattch <= 0) {
-        ShmFreeSeg(seg);
+    ShmPagesRefDec(seg);//ref -- 
+    seg->ds.shm_nattch--;//附在共享线性区上的进程数--
+    if (seg->ds.shm_nattch <= 0) {//没有任何进程在使用这个线性区的情况
+        ShmFreeSeg(seg);//就释放掉物理内存!注意是:物理内存
     }
     SYSV_SHM_UNLOCK();
 }
-//是否为共享线性区
+//是否为共享线性区,看他有没有标签
 BOOL OsIsShmRegion(LosVmMapRegion *region)
 {
     return (region->regionFlags & VM_MAP_REGION_FLAG_SHM) ? TRUE : FALSE;
 }
-
+//使用共享段数量
 STATIC INT32 ShmSegUsedCount(VOID)
 {
     INT32 i;

zzz/git/push.sh

 git add -A
-git commit -m  'CPU硬件上下文 及其各种寄存器，异常处理函数的注释
+git commit -m  '完善进程部分注释,注释进程是怎么一步步被Fork的
 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.'