鸿蒙内核源码分析系列篇 https://blog.csdn.net/kuangyufei

kernel/base/include/los_vm_map.h

@@ -171,10 +171,10 @@ typedef struct VmSpace {
 #define     VM_MAP_REGION_FLAG_FLAG_MASK            (3<<7)		//掩码用途
 #define     VM_MAP_REGION_FLAG_STACK                (1<<9)		//栈区
 #define     VM_MAP_REGION_FLAG_HEAP                 (1<<10)		//堆区
-#define     VM_MAP_REGION_FLAG_DATA                 (1<<11)		//数据区
+#define     VM_MAP_REGION_FLAG_DATA                 (1<<11)		//data数据区 编译在ELF中
 #define     VM_MAP_REGION_FLAG_TEXT                 (1<<12)		//代码区
-#define     VM_MAP_REGION_FLAG_BSS                  (1<<13)		//bbs数据区
-#define     VM_MAP_REGION_FLAG_VDSO                 (1<<14)		//映射区
+#define     VM_MAP_REGION_FLAG_BSS                  (1<<13)		//bbs数据区 由运行时动态分配
+#define     VM_MAP_REGION_FLAG_VDSO                 (1<<14)		//虚拟动态链接对象（Virtual Dynamically Shared Object、vDSO
 #define     VM_MAP_REGION_FLAG_MMAP                 (1<<15)		//映射区
 #define     VM_MAP_REGION_FLAG_SHM                  (1<<16) 	//共享内存区
 #define     VM_MAP_REGION_FLAG_INVALID              (1<<17) /* indicates that flags are not specified */
@@ -224,7 +224,7 @@ STATIC INLINE BOOL LOS_IsRegionPermUserReadOnly(LosVmMapRegion* region)
     return ((region->regionFlags & VM_MAP_REGION_FLAG_PROT_MASK) ==
             (VM_MAP_REGION_FLAG_PERM_USER | VM_MAP_REGION_FLAG_PERM_READ));
 }
-//私有线性区
+//是否为私有线性区
 STATIC INLINE BOOL LOS_IsRegionFlagPrivateOnly(LosVmMapRegion* region)
 {
     return ((region->regionFlags & VM_MAP_REGION_FLAG_FLAG_MASK) == VM_MAP_REGION_FLAG_PRIVATE);
@@ -234,33 +234,33 @@ STATIC INLINE VOID LOS_SetRegionTypeFile(LosVmMapRegion* region)
 {
     region->regionType = VM_MAP_REGION_TYPE_FILE;
 }
-
+//是否为设备映射线性区
 STATIC INLINE BOOL LOS_IsRegionTypeDev(LosVmMapRegion* region)
 {
     return region->regionType == VM_MAP_REGION_TYPE_DEV;
 }
-
+//设为设备映射线性区
 STATIC INLINE VOID LOS_SetRegionTypeDev(LosVmMapRegion* region)
 {
     region->regionType = VM_MAP_REGION_TYPE_DEV;
 }
-
+//是否为匿名swap映射线性区
 STATIC INLINE BOOL LOS_IsRegionTypeAnon(LosVmMapRegion* region)
 {
     return region->regionType == VM_MAP_REGION_TYPE_ANON;
 }
-
+//设为匿名swap映射线性区
 STATIC INLINE VOID LOS_SetRegionTypeAnon(LosVmMapRegion* region)
 {
     region->regionType = VM_MAP_REGION_TYPE_ANON;
 }
-
+//虚拟地址是否在用户空间
 STATIC INLINE BOOL LOS_IsUserAddress(VADDR_T vaddr)
 {
     return ((vaddr >= USER_ASPACE_BASE) &&
             (vaddr <= (USER_ASPACE_BASE + (USER_ASPACE_SIZE - 1))));
 }
-
+//从vaddr 到 vaddr + len 这段虚拟地址是否在用户空间
 STATIC INLINE BOOL LOS_IsUserAddressRange(VADDR_T vaddr, size_t len)
 {
     return (vaddr + len > vaddr) && LOS_IsUserAddress(vaddr) && (LOS_IsUserAddress(vaddr + len - 1));

kernel/base/include/los_vm_page.h

@@ -54,8 +54,8 @@ typedef struct VmPage {
     UINT16              nPages;      /**< the vm page is used for kernel heap */
 } LosVmPage;
 
-extern LosVmPage *g_vmPageArray;//物理内存所有页记录数组
-extern size_t g_vmPageArraySize;//物理内存总页数
+extern LosVmPage *g_vmPageArray;//物理内存所有页框(page frame)记录数组
+extern size_t g_vmPageArraySize;//物理内存总页框(page frame)数
 
 LosVmPage *LOS_VmPageGet(PADDR_T paddr);
 VOID OsVmPageStartup(VOID);

kernel/base/include/los_vm_phys.h

@@ -52,12 +52,12 @@ extern "C" {
 
 #define VM_PAGE_TO_PHYS(page)    (page->physAddr)//获取页面物理地址
 #define VM_ORDER_TO_PAGES(order) (1 << (order))//伙伴算法由order 定位到该块组的页面单位,例如:order=2时，page[4]
-#define VM_ORDER_TO_PHYS(order)  (1 << (PAGE_SHIFT + (order)))//通过order找物理地址
+#define VM_ORDER_TO_PHYS(order)  (1 << (PAGE_SHIFT + (order)))//跳块例如 order=2 就是跳4页
 #define VM_PHYS_TO_ORDER(phys)   (min(LOS_LowBitGet((phys) >> PAGE_SHIFT), VM_LIST_ORDER_MAX - 1))//通过物理地址定位到order
 
 struct VmFreeList {
-    LOS_DL_LIST node;
-    UINT32 listCnt;
+    LOS_DL_LIST node;	//双循环链表
+    UINT32 listCnt;		//双循环链表节点总数
 };
 //针对匿名页和文件页各拆分成一个活跃，一个不活跃的链表。
 enum OsLruList {

kernel/base/mem/bestfit/los_memory.c

@@ -1561,7 +1561,7 @@ STATIC INLINE INT32 OsMemPoolExpand(VOID *pool, UINT32 size, UINT32 intSave)
     endNode = (LosMemDynNode *)OS_MEM_END_NODE(pool, poolInfo->poolSize);
 
 RETRY:
-    newNode = (LosMemDynNode *)LOS_PhysPagesAllocContiguous(size >> PAGE_SHIFT);
+    newNode = (LosMemDynNode *)LOS_PhysPagesAllocContiguous(size >> PAGE_SHIFT);//分配连续的物理内存
     if (newNode == NULL) {
         if (tryCount > 0) {
             tryCount--;

kernel/base/vm/los_vm_boot.c

@@ -44,9 +44,9 @@ extern "C" {
 #endif /* __cplusplus */
 #endif /* __cplusplus */
 
-UINTPTR g_vmBootMemBase = (UINTPTR)&__bss_end;//内核空间的
+UINTPTR g_vmBootMemBase = (UINTPTR)&__bss_end;//内核空间可用于分配的区域
 BOOL g_kHeapInited = FALSE;//内核堆区初始化变量
-
+//虚拟内存区间检查, 需理解 los_vm_zone.h 中画出的鸿蒙虚拟内存全景图
 UINT32 OsVmAddrCheck(size_t tempAddr, size_t length)
 {
     if ((tempAddr >= KERNEL_VMM_BASE) && ((tempAddr + length) <= (PERIPH_UNCACHED_BASE + PERIPH_UNCACHED_SIZE))) {
@@ -60,7 +60,7 @@ VOID *OsVmBootMemAlloc(size_t len)
 {
     UINTPTR ptr;
 
-    if (g_kHeapInited) {//g_kHeapInited 在什么时候会变成 true？没找到代码
+    if (g_kHeapInited) {// ??? g_kHeapInited 在什么时候会变成 true,没找到代码
         VM_ERR("kernel heap has been inited, should not to use boot mem alloc!");
         return NULL;
     }

kernel/base/vm/los_vm_page.c

@@ -94,8 +94,8 @@ LosVmPage *LOS_VmPageGet(PADDR_T paddr)
     INT32 segID;
     LosVmPage *page = NULL;
 
-    for (segID = 0; segID < g_vmPhysSegNum; segID++) {
-        page = OsVmPhysToPage(paddr, segID);
+    for (segID = 0; segID < g_vmPhysSegNum; segID++) {//物理内存采用段页管理
+        page = OsVmPhysToPage(paddr, segID);//通过物理地址和段ID找出物理页框
         if (page != NULL) {
             break;
         }

kernel/base/vm/los_vm_phys.c

@@ -45,35 +45,35 @@ extern "C" {
 #define ONE_PAGE    1
 
 /* Physical memory area array */
-STATIC struct VmPhysArea g_physArea[] = {
+STATIC struct VmPhysArea g_physArea[] = {//这里只整了一个区域,即只生成一个段,鸿蒙物理内存采用段页式管理
     {
         .start = SYS_MEM_BASE, //整个物理内存基地址
         .size = SYS_MEM_SIZE_DEFAULT,//整个物理内存总大小
     },
 };
 
-struct VmPhysSeg g_vmPhysSeg[VM_PHYS_SEG_MAX];//32段
-INT32 g_vmPhysSegNum = 0;
-
+struct VmPhysSeg g_vmPhysSeg[VM_PHYS_SEG_MAX];//最大32段
+INT32 g_vmPhysSegNum = 0;	//段数
+//获取段数组,全局变量,变量放在 .bbs 区
 LosVmPhysSeg *OsGVmPhysSegGet()
 {
     return g_vmPhysSeg;
 }
-
+//初始化Lru置换 LRU list 在 VmPhysSeg中管理
 STATIC VOID OsVmPhysLruInit(struct VmPhysSeg *seg)
 {
     INT32 i;
     UINT32 intSave;
-    LOS_SpinInit(&seg->lruLock);
+    LOS_SpinInit(&seg->lruLock);//自旋锁,自旋锁用户CPU多核同步
 
     LOS_SpinLockSave(&seg->lruLock, &intSave);
-    for (i = 0; i < VM_NR_LRU_LISTS; i++) {
-        seg->lruSize[i] = 0;
-        LOS_ListInit(&seg->lruList[i]);
+    for (i = 0; i < VM_NR_LRU_LISTS; i++) { //五个双循环链表
+        seg->lruSize[i] = 0;	//记录链表节点数
+        LOS_ListInit(&seg->lruList[i]);//初始化LRU链表
     }
     LOS_SpinUnlockRestore(&seg->lruLock, intSave);
 }
-
+//创建物理段
 STATIC INT32 OsVmPhysSegCreate(paddr_t start, size_t size)
 {
     struct VmPhysSeg *seg = NULL;
@@ -98,14 +98,14 @@ VOID OsVmPhysSegAdd(VOID)
 
     LOS_ASSERT(g_vmPhysSegNum <= VM_PHYS_SEG_MAX);
 	
-    for (i = 0; i < (sizeof(g_physArea) / sizeof(g_physArea[0])); i++) {
+    for (i = 0; i < (sizeof(g_physArea) / sizeof(g_physArea[0])); i++) {//将g_physArea转化成段
         ret = OsVmPhysSegCreate(g_physArea[i].start, g_physArea[i].size);//一个区对应一个段
         if (ret != 0) {
             VM_ERR("create phys seg failed");
         }
     }
 }
-
+//段区域大小调整
 VOID OsVmPhysAreaSizeAdjust(size_t size)
 {
     INT32 i;
@@ -127,24 +127,24 @@ UINT32 OsVmPhysPageNumGet(VOID)
 
     return nPages;
 }
-
+//初始化空闲链表,分配页框使用伙伴算法
 STATIC INLINE VOID OsVmPhysFreeListInit(struct VmPhysSeg *seg)
 {
     int i;
     UINT32 intSave;
     struct VmFreeList *list = NULL;
 
-    LOS_SpinInit(&seg->freeListLock);
+    LOS_SpinInit(&seg->freeListLock);//自旋锁
 
     LOS_SpinLockSave(&seg->freeListLock, &intSave);
     for (i = 0; i < VM_LIST_ORDER_MAX; i++) {
         list = &seg->freeList[i];
-        LOS_ListInit(&list->node);
+        LOS_ListInit(&list->node);//初始化9个链表 2|0,2|1,2|2 分配页框 |代表次方的意思
         list->listCnt = 0;
     }
     LOS_SpinUnlockRestore(&seg->freeListLock, intSave);
 }
-
+//段初始化
 VOID OsVmPhysInit(VOID)
 {
     struct VmPhysSeg *seg = NULL;
@@ -153,13 +153,13 @@ VOID OsVmPhysInit(VOID)
 
     for (i = 0; i < g_vmPhysSegNum; i++) {
         seg = &g_vmPhysSeg[i];
-        seg->pageBase = &g_vmPageArray[nPages];
-        nPages += seg->size >> PAGE_SHIFT;
-        OsVmPhysFreeListInit(seg);
-        OsVmPhysLruInit(seg);
+        seg->pageBase = &g_vmPageArray[nPages];//
+        nPages += seg->size >> PAGE_SHIFT;//偏移12位,因以页管理,本段总页数
+        OsVmPhysFreeListInit(seg);	//初始化空闲链表,分配页框使用伙伴算法
+        OsVmPhysLruInit(seg);		//初始化LRU置换链表
     }
 }
-
+//将页框挂入空闲链表,供分配
 STATIC VOID OsVmPhysFreeListAdd(LosVmPage *page, UINT8 order)
 {
     struct VmPhysSeg *seg = NULL;
@@ -169,12 +169,12 @@ STATIC VOID OsVmPhysFreeListAdd(LosVmPage *page, UINT8 order)
         LOS_Panic("The page segment id(%d) is invalid\n", page->segID);
     }
 
-    page->order = order;
-    seg = &g_vmPhysSeg[page->segID];
+    page->order = order;// page记录 块组号
+    seg = &g_vmPhysSeg[page->segID];//先找到所属段
 
-    list = &seg->freeList[order];
-    LOS_ListTailInsert(&list->node, &page->node);
-    list->listCnt++;
+    list = &seg->freeList[order];//找到对应List
+    LOS_ListTailInsert(&list->node, &page->node);//将page节点挂入链表
+    list->listCnt++;//链表内的节点总数++
 }
 
 STATIC VOID OsVmPhysFreeListAddUnsafe(LosVmPage *page, UINT8 order)
@@ -264,23 +264,23 @@ VOID *OsVmPageToVaddr(LosVmPage *page)//
 	//内核空间的vmPage是不会被置换的，所以是常驻内存，内核空间初始化mmu时就映射好了L1表
     return (VOID *)(UINTPTR)vaddr;
 }
-
+//通过虚拟地址找映射的物理页框
 LosVmPage *OsVmVaddrToPage(VOID *ptr)
 {
     struct VmPhysSeg *seg = NULL;
-    PADDR_T pa = LOS_PaddrQuery(ptr);
+    PADDR_T pa = LOS_PaddrQuery(ptr);//通过虚拟地址查询物理地址
     UINT32 segID;
 
     for (segID = 0; segID < g_vmPhysSegNum; segID++) {
         seg = &g_vmPhysSeg[segID];
         if ((pa >= seg->start) && (pa < (seg->start + seg->size))) {
-            return seg->pageBase + ((pa - seg->start) >> PAGE_SHIFT);
+            return seg->pageBase + ((pa - seg->start) >> PAGE_SHIFT);//段基地址+页偏移索引 得到虚拟地址经映射所在物理页框
         }
     }
 
     return NULL;
 }
-
+//从段中分配指定页框数
 LosVmPage *OsVmPhysPagesAlloc(struct VmPhysSeg *seg, size_t nPages)
 {
     struct VmFreeList *list = NULL;
@@ -293,7 +293,7 @@ LosVmPage *OsVmPhysPagesAlloc(struct VmPhysSeg *seg, size_t nPages)
     }
 
     order = OsVmPagesToOrder(nPages);//根据页数计算出用哪个块组
-    if (order < VM_LIST_ORDER_MAX) {
+    if (order < VM_LIST_ORDER_MAX) {//order不能大于9 即:256*4K = 1M 可理解为向内核堆申请内存一次不能超过1M
         for (newOrder = order; newOrder < VM_LIST_ORDER_MAX; newOrder++) {//没有就找更大块
             list = &seg->freeList[newOrder];//从最合适的块处开始找
             if (LOS_ListEmpty(&list->node)) {//没找到
@@ -309,7 +309,7 @@ DONE:
     OsVmPhysPagesSpiltUnsafe(page, order, newOrder);
     return page;
 }
-
+//释放物理页,所谓释放物理页就是把页挂到空闲链表中
 VOID OsVmPhysPagesFree(LosVmPage *page, UINT8 order)
 {
     paddr_t pa;
@@ -320,14 +320,14 @@ VOID OsVmPhysPagesFree(LosVmPage *page, UINT8 order)
     }
 
     if (order < VM_LIST_ORDER_MAX - 1) {//order[0,7]
-        pa = VM_PAGE_TO_PHYS(page);
+        pa = VM_PAGE_TO_PHYS(page);//获取物理地址
         do {
-            pa ^= VM_ORDER_TO_PHYS(order);
-            buddyPage = OsVmPhysToPage(pa, page->segID);
+            pa ^= VM_ORDER_TO_PHYS(order);//注意这里是高位和低位的^=,也就是说跳到 order块组 物理地址处,此处处理甚妙!
+            buddyPage = OsVmPhysToPage(pa, page->segID);//如此就能拿到以2的order次方跳的buddyPage
             if ((buddyPage == NULL) || (buddyPage->order != order)) {
                 break;
             }
-            OsVmPhysFreeListDel(buddyPage);
+            OsVmPhysFreeListDel(buddyPage);//注意buddypage是连续的物理页框 例如order=2时,连续的4页就是一个块组 |_|_|_|_| 
             order++;
             pa &= ~(VM_ORDER_TO_PHYS(order) - 1);
             page = OsVmPhysToPage(pa, page->segID);
@@ -363,7 +363,7 @@ VOID OsVmPhysPagesFreeContiguous(LosVmPage *page, size_t nPages)
         page += n;
     }
 }
-
+//获取一定数量的页框
 STATIC LosVmPage *OsVmPhysPagesGet(size_t nPages)
 {
     UINT32 intSave;
@@ -378,11 +378,11 @@ STATIC LosVmPage *OsVmPhysPagesGet(size_t nPages)
     for (segID = 0; segID < g_vmPhysSegNum; segID++) {
         seg = &g_vmPhysSeg[segID];
         LOS_SpinLockSave(&seg->freeListLock, &intSave);
-        page = OsVmPhysPagesAlloc(seg, nPages);
+        page = OsVmPhysPagesAlloc(seg, nPages);//分配指定页数的物理页, 可分析出 nPages 不能大于 256个
         if (page != NULL) {
             /*  */
             LOS_AtomicSet(&page->refCounts, 0);//设置引用次数为0
-            page->nPages = nPages;
+            page->nPages = nPages;//页数
             LOS_SpinUnlockRestore(&seg->freeListLock, intSave);
             return page;
         }
@@ -398,7 +398,7 @@ VOID *LOS_PhysPagesAllocContiguous(size_t nPages)
     if (nPages == 0) {
         return NULL;
     }
-
+	//鸿蒙 nPages 不能大于 2的8 次方,即256个页,1M内存,仅限于内核态,用户态不限制分配大小.
     page = OsVmPhysPagesGet(nPages);//通过伙伴算法获取物理上连续的页
     if (page == NULL) {
         return NULL;
@@ -542,7 +542,7 @@ struct VmPhysSeg *OsVmPhysSegGet(LosVmPage *page)
 
     return (OsGVmPhysSegGet() + page->segID);
 }
-
+//通过总页数 ,获取块组 ,例如需要分配 8个页,返回就是 3 ,例如 1023个 返回就是 10
 UINT32 OsVmPagesToOrder(size_t nPages)
 {
     UINT32 order;

wtest/main.c

@@ -5,6 +5,8 @@ typedef unsigned long PTE_T;
 typedef unsigned long VADDR_T;
 #define IS_ALIGNED(a, b)                 (!(((UINTPTR)(a)) & (((UINTPTR)(b)) - 1)))
 
+//鸿蒙内核源码分析系列篇 https://blog.csdn.net/kuangyufei
+
 void b(){
     UINT8 w[3]={0};
     PTE_T pte1BasePtr = 0x11100000;

wtest/push.sh

+git add -A
+git commit -m  "鸿蒙内核源码分析系列篇 https://blog.csdn.net/kuangyufei"
+git push