鸿蒙内核加EMI界面,鸿蒙内核源码分析（内存分配篇）：内存的分配方式有哪些...

/* Physical memory area array */

STATIC struct VmPhysArea g_physArea[] = {

{

.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

},

};

//* page初始化

VOID OsVmPageStartup(VOID)

{

struct VmPhysSeg *seg = NULL;

LosVmPage *page = NULL;

paddr_t pa;

UINT32 nPage;

INT32 segID;

OsVmPhysAreaSizeAdjust(ROUNDUP((g_vmBootMemBase - KERNEL_ASPACE_BASE), PAGE_SIZE));//校正 g_physArea size

nPage = OsVmPhysPageNumGet();//得到 g_physArea 总页数

g_vmPageArraySize = nPage * sizeof(LosVmPage);//页表总大小

g_vmPageArray = (LosVmPage *)OsVmBootMemAlloc(g_vmPageArraySize);//申请页表存放区域

OsVmPhysAreaSizeAdjust(ROUNDUP(g_vmPageArraySize, PAGE_SIZE));// g_physArea 变小

OsVmPhysSegAdd();// 段页绑定

OsVmPhysInit();// 加入空闲链表和设置置换算法,LRU(最近最久未使用)算法

for (segID = 0; segID < g_vmPhysSegNum; segID++) {

seg = &g_vmPhysSeg[segID];

nPage = seg->size >> PAGE_SHIFT;

for (page = seg->pageBase, pa = seg->start; page <= seg->pageBase + nPage;

page++, pa += PAGE_SIZE) {

OsVmPageInit(page, pa, segID);//page初始化

}

OsVmPageOrderListInit(seg->pageBase, nPage);// 页面分配的排序

}

}

UINT32 OsVmPhysPageNumGet(VOID)

{

UINT32 nPages = 0;

INT32 i;

for (i = 0; i < (sizeof(g_physArea) / sizeof(g_physArea[0])); i++) {

nPages += g_physArea[i].size >> PAGE_SHIFT;//右移12位，相当于除以4K,得出总页数

}

return nPages;

}

VOID OsVmPhysSegAdd(VOID)

{

INT32 i, ret;

LOS_ASSERT(g_vmPhysSegNum <= VM_PHYS_SEG_MAX);

for (i = 0; i < (sizeof(g_physArea) / sizeof(g_physArea[0])); i++) {

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");

}

}

}

STATIC VOID OsVmPageInit(LosVmPage *page, paddr_t pa, UINT8 segID)

{

LOS_ListInit(&page->node);//初始化链表节点

page->flags = FILE_PAGE_FREE;//默认空闲

LOS_AtomicSet(&page->refCounts, 0);//0次引用

page->physAddr = pa;//物理地址

page->segID = segID;//所属段

page->order = VM_LIST_ORDER_MAX;//伙伴算法默认级数

}