!77 Optimization for physics memory

Merge pull request !77 from Harylee/master

kernel/base/vm/los_vm_page.c

@@ -76,7 +76,12 @@ VOID OsVmPageStartup(VOID)
 
     OsVmPhysAreaSizeAdjust(ROUNDUP((g_vmBootMemBase - KERNEL_ASPACE_BASE), PAGE_SIZE));
 
-    nPage = OsVmPhysPageNumGet();
+    /*
+     * Pages getting from OsVmPhysPageNumGet() interface here contain the memory
+     * struct LosVmPage occupied, which satisfies the equation:
+     * nPage * sizeof(LosVmPage) + nPage * PAGE_SIZE = OsVmPhysPageNumGet() * PAGE_SIZE.
+     */
+    nPage = OsVmPhysPageNumGet() * PAGE_SIZE / (sizeof(LosVmPage) + PAGE_SIZE);
     g_vmPageArraySize = nPage * sizeof(LosVmPage);
     g_vmPageArray = (LosVmPage *)OsVmBootMemAlloc(g_vmPageArraySize);
 

kernel/base/vm/los_vm_phys.c

@@ -108,12 +108,12 @@ VOID OsVmPhysSegAdd(VOID)
 
 VOID OsVmPhysAreaSizeAdjust(size_t size)
 {
-    INT32 i;
-
-    for (i = 0; i < (sizeof(g_physArea) / sizeof(g_physArea[0])); i++) {
-        g_physArea[i].start += size;
-        g_physArea[i].size -= size;
-    }
+    /*
+     * The first physics memory segment is used for kernel image and kernel heap,
+     * so just need to adjust the first one here.
+     */
+    g_physArea[0].start += size;
+    g_physArea[0].size -= size;
 }
 
 UINT32 OsVmPhysPageNumGet(VOID)