diff --git a/study/memdev/Makefile b/study/memdev/mem/Makefile
similarity index 100%
rename from study/memdev/Makefile
rename to study/memdev/mem/Makefile
diff --git a/study/memdev/mem_dev.c b/study/memdev/mem/mem_dev.c
similarity index 97%
rename from study/memdev/mem_dev.c
rename to study/memdev/mem/mem_dev.c
index dac4132..824aaab 100644
--- a/study/memdev/mem_dev.c
+++ b/study/memdev/mem/mem_dev.c
@@ -27,7 +27,6 @@ long writePhysicsAddress(unsigned long pa, unsigned long data, int *pStatus);
 
 static int mem_dev_init(void)
 {
-
     readPhysicsAddress(0x12345, NULL);
     return 0;
 }
@@ -46,7 +45,6 @@ static void mem_dev_exit(void)
 long readPhysicsAddress(unsigned long pa, int *pStatus)
 {
     long data = -1;
-    //long *point = (long *)pa;
     data = *(long *)pa;
     printk(KERN_INFO "physics address : 0x%lx, data : 0x%lx", pa, data);
 
diff --git a/study/memdev/devkmem.c b/study/memdev/mmap/devkmem.c
similarity index 100%
rename from study/memdev/devkmem.c
rename to study/memdev/mmap/devkmem.c
diff --git a/study/memdev/devmem.c b/study/memdev/mmap/devmem.c
similarity index 100%
rename from study/memdev/devmem.c
rename to study/memdev/mmap/devmem.c
diff --git a/study/memdev/getjiff.c b/study/memdev/mmap/getjiff.c
similarity index 100%
rename from study/memdev/getjiff.c
rename to study/memdev/mmap/getjiff.c
diff --git a/study/memdev/v2p/Makefile b/study/memdev/v2p/Makefile
new file mode 100644
index 0000000..44b40c0
--- /dev/null
+++ b/study/memdev/v2p/Makefile
@@ -0,0 +1,14 @@
+
+
+obj-m := v2p.o
+
+KERNELDIR ?= /lib/modules/$(shell uname -r)/build
+
+PWD := $(shell pwd)
+
+all:
+	make -C $(KERNELDIR) M=$(PWD) modules
+
+clean:
+	make -C $(KERNELDIR) M=$(PWD) clean
+
diff --git a/study/memdev/v2p/Module.markers b/study/memdev/v2p/Module.markers
new file mode 100644
index 0000000..e69de29
diff --git a/study/memdev/v2p/Module.symvers b/study/memdev/v2p/Module.symvers
new file mode 100644
index 0000000..e69de29
diff --git a/study/memdev/v2p/v2p.c b/study/memdev/v2p/v2p.c
new file mode 100644
index 0000000..fe416d8
--- /dev/null
+++ b/study/memdev/v2p/v2p.c
@@ -0,0 +1,106 @@
+/*****************************************************************
+文件名：mem.c
+输入参数：
+pid 接收待查询进程的PID
+va 接收待查询的虚拟地址
+*****************************************************************/
+
+
+#include  <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <asm/pgtable.h>
+#include <asm/page.h>
+
+MODULE_LICENSE("GPL");
+static int pid;
+static unsigned long va;
+
+module_param(pid,int,0644);
+module_param(va,ulong,0644);
+
+static int find_pgd_init(void)
+{
+        unsigned long pa = 0;
+        struct task_struct *pcb_tmp = NULL;
+        pgd_t *pgd_tmp = NULL;
+        pud_t *pud_tmp = NULL;
+        pmd_t *pmd_tmp = NULL;
+        pte_t *pte_tmp = NULL;
+
+        printk(KERN_INFO"PAGE_OFFSET = 0x%lx\n",PAGE_OFFSET);
+        printk(KERN_INFO"PGDIR_SHIFT = %d\n",PGDIR_SHIFT);
+        printk(KERN_INFO"PUD_SHIFT = %d\n",PUD_SHIFT);
+        printk(KERN_INFO"PMD_SHIFT = %d\n",PMD_SHIFT);
+        printk(KERN_INFO"PAGE_SHIFT = %d\n",PAGE_SHIFT);
+
+        printk(KERN_INFO"PTRS_PER_PGD = %d\n",PTRS_PER_PGD);
+        printk(KERN_INFO"PTRS_PER_PUD = %d\n",PTRS_PER_PUD);
+        printk(KERN_INFO"PTRS_PER_PMD = %d\n",PTRS_PER_PMD);
+        printk(KERN_INFO"PTRS_PER_PTE = %d\n",PTRS_PER_PTE);
+
+        printk(KERN_INFO"PAGE_MASK = 0x%lx\n",PAGE_MASK);
+
+        if(!(pcb_tmp = find_task_by_pid(pid))) {
+                printk(KERN_INFO"Can't find the task %d .\n",pid);
+                return 0;
+        }
+        printk(KERN_INFO"pgd = 0x%p\n",pcb_tmp->mm->pgd);
+                /* 判断给出的地址va是否合法(va&lt;vm_end)*/
+        if(!find_vma(pcb_tmp->mm,va)){
+                printk(KERN_INFO"virt_addr 0x%lx not available.\n",va);
+                return 0;
+        }
+        pgd_tmp = pgd_offset(pcb_tmp->mm,va);
+        printk(KERN_INFO"pgd_tmp = 0x%p\n",pgd_tmp);
+        printk(KERN_INFO"pgd_val(*pgd_tmp) = 0x%lx\n",pgd_val(*pgd_tmp));
+        if(pgd_none(*pgd_tmp)){
+                printk(KERN_INFO"Not mapped in pgd.\n");
+                return 0;
+        }
+        pud_tmp = pud_offset(pgd_tmp,va);
+        printk(KERN_INFO"pud_tmp = 0x%p\n",pud_tmp);
+        printk(KERN_INFO"pud_val(*pud_tmp) = 0x%lx\n",pud_val(*pud_tmp));
+        if(pud_none(*pud_tmp)){
+                printk(KERN_INFO"Not mapped in pud.\n");
+                return 0;
+        }
+        pmd_tmp = pmd_offset(pud_tmp,va);
+        printk(KERN_INFO"pmd_tmp = 0x%p\n",pmd_tmp);
+        printk(KERN_INFO"pmd_val(*pmd_tmp) = 0x%lx\n",pmd_val(*pmd_tmp));
+        if(pmd_none(*pmd_tmp)){
+                printk(KERN_INFO"Not mapped in pmd.\n");
+                return 0;
+        }
+        /*在这里，把原来的pte_offset_map()改成了pte_offset_kernel*/
+        pte_tmp = pte_offset_kernel(pmd_tmp,va);
+
+        printk(KERN_INFO"pte_tmp = 0x%p\n",pte_tmp);
+        printk(KERN_INFO"pte_val(*pte_tmp) = 0x%lx\n",pte_val(*pte_tmp));
+        if(pte_none(*pte_tmp)){
+                printk(KERN_INFO"Not mapped in pte.\n");
+                return 0;
+        }
+        if(!pte_present(*pte_tmp)){
+                printk(KERN_INFO"pte not in RAM.\n");
+                return 0;
+        }
+        pa = (pte_val(*pte_tmp) & PAGE_MASK) |(va & ~PAGE_MASK);
+        printk(KERN_INFO"virt_addr 0x%lx in RAM is 0x%lx t .\n",va,pa);
+        printk(KERN_INFO"contect in 0x%lx is 0x%lx\n",pa,
+                *(unsigned long *)((char *)pa + PAGE_OFFSET));
+
+        return 0;
+
+}
+
+static void  find_pgd_exit(void)
+{
+        printk(KERN_INFO"Goodbye!\n");
+
+}
+
+module_init(find_pgd_init);
+module_exit(find_pgd_exit);