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本帖最后由 duanjigang 于 2010-06-01 10:45 编辑
cme_mem_20100601.tar.gz
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cme_mem_20100201.tar.gz
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修改历史:
2010-02-01:
首先是把节点中的list和ptr改成 head 和tail了,为了方便理解,老炮给的意见
另外是,在节点中添加了一个raw_data指针,跟data在初始化时同时指向数据内存地址,这样做的目的是防止
用户在退出时忘记了free每一个node,如果采用以前的方式,整个内存池也就忘记Free了,虽然能够在退出时提示开发者,
修改后,能够在提示开发者的基础上释放未被释放的节点。
2010-06-01;
修改内容:其一,初始化N个节点时,为了保留栈的地址,须预留一个节点,因此最多只能申请到N-1个,做了修改,我们在实际开辟时申请N+1个,这样对用户就透明了。其二:new_mem_node时。需要把当前栈顶的节点的data置空,当时写错了,搞成了栈底节点的data置空,虽然不影响功能,但逻辑错误,做了修改。
######################################################################
简单技术含量不高还敢说,易用就看各位的反响了 ,期待更好的改进建议。
自己根据实际工作需要写的,主要是为了省事,稍微提高点效率,省下了N多数组的声明和调用。
把多个类型的内存节点集合到一起统一管理,初始化时统一初始化,调用如下:- init_mem_list (TYPE_S1, sizeof(s1_t), 100);
- init_mem_list (TYPE_S2, sizeof(s2_t), 200);
复制代码 退出时统一释放,调用如下:运行过程中调用
调用封装的new和free函数- extern u_int8_t * new_mem_node(u_int8_t type);
- extern void free_mem_node( u_int8_t * addr);
复制代码 个人感觉还是比较方便的,效率相对还比较高,首先根据类型哈希到对应的链表上,然后每个链表就是一个栈,弹栈或者压栈就是new和Free操作。
一个简单的使用例子如下:
//cme_hook.c
#include <linux/module.h>
#include <linux/kernel.h>
#include "head.h"
#include "mem_pool.c"
typedef struct
{
u_int16_t key1;
u_int32_t key2;
}s1_t;
typedef struct
{
u_int8_t key1;
u_int16_t key2;
}s2_t;
const u_int8_t TYPE_S1 = 1;
const u_int8_t TYPE_S2 = 2;
s1_t* s1_list[20];
s2_t* s2_list[50];
int init(void)
{
int i = 0;
init_mem_list (TYPE_S1, sizeof(s1_t), 100);
init_mem_list (TYPE_S2, sizeof(s2_t), 200);
for (i = 0; i < 20; i++)
{
s1_list[i] = (s1_t*)new_mem_node(TYPE_S1);
s1_list[i]->key1 = 2*i;
s1_list[i]->key2 = 2*i+1;
}
for (i = 0; i < 50; i++)
{
s2_list[i] = (s2_t*)new_mem_node(TYPE_S2);
s2_list[i]->key1 = 3*i;
s2_list[i]->key2 = 3*i+1;
}
for (i = 0; i < 20; i++)
{
printk("s1_list[%d]=<%u, %u>\n", i, s1_list[i]->key1, s1_list[i]->key2);
}
for (i = 0; i < 50; i++)
{
printk("s2_list[%d]=<%u, %u>\n", i, s2_list[i]->key1, s2_list[i]->key2);
}
printk("cme hook registering.......\n");
return 0;
}
void finish(void)
{
int i = 0;
for (i = 0; i < 20; i++) free_mem_node(((u_int8_t*)s1_list[i]));
for (i = 0; i < 50; i++) free_mem_node(((u_int8_t*)s2_list[i]));
clean_mem_list();
printk("removing cme hook.......\n");
}
module_init(init)
module_exit(finish)
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");
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附件是例子完整代码以及这个小小内存池的实现代码,大家多多提意见改进。
#######################################
附件看不到,贴下mem_pool.c中的实现代码
//mem_pool.c
#include <linux/module.h>
#include <linux/kernel.h>
#include "head.h"
int print_msg = 0;
#define MAX_MEM_LIST 256
typedef struct _node
{
u_int8_t * data;
struct _node * next;
struct _node * pre;
}mem_node_t;
typedef struct
{
mem_node_t * list;
mem_node_t * ptr;
spinlock_t lock;
u_int8_t type;
u_int8_t valid;
}mem_list_t;
static mem_list_t mem_list[MAX_MEM_LIST];
static int init_all_mem_list(void)
{
int i = 0;
for (i = 0; i < MAX_MEM_LIST; i++)
{
mem_list[i].list = NULL;
mem_list[i].ptr = NULL;
mem_list[i].type = 0;
mem_list[i].valid = 0;
}
return 1;
}
static int mem_list_init = 0;
u_int8_t * new_mem_node(u_int8_t type)
{
u_int8_t * prt = NULL;
mem_node_t * plist = mem_list[type].list;
if(!plist) return NULL;
spin_lock(&mem_list[type].lock);
if(mem_list[type].ptr != mem_list[type].list)
{
prt = (u_int8_t*)(mem_list[type].ptr->data + 1);
if(print_msg) printk("alloc one node:%p\n", prt);
plist->data = NULL;
mem_list[type].ptr = mem_list[type].ptr->pre;
}else
{
if(print_msg) printk("no node for alloc\n");
}
spin_unlock(&mem_list[type].lock);
return prt;
}
void free_mem_node( u_int8_t * addr)
{
u_int8_t type = *(addr - 1);
mem_list_t * plist = &mem_list[type];
spin_lock(&plist->lock);
if(plist->ptr->next && addr)
{
if(print_msg) printk("free one mem node %p of type:%u\n", addr, type);
plist->ptr = plist->ptr->next;
plist->ptr->data = (u_int8_t*)(addr-1);
}else
{
if(print_msg) printk("free node error\n");
}
spin_unlock(&plist->lock);
}
int init_mem_list ( u_int8_t type, int size, int length)
{
int i = 0;
mem_list_t * plist = &mem_list[i];
if (!mem_list_init)
{
init_all_mem_list();
mem_list_init = 1;
}
if ((type == 0)||(size <= 0) || (length <= 0)) return 0;
plist = &mem_list[type];
if(plist->valid) return 1;
plist->valid = 1;
spin_lock_init(&plist->lock);
plist->type = type;
for ( i = 0; i < length; i++ )
{
u_int8_t * ptype = 0;
mem_node_t * p = (mem_node_t*)malloc(sizeof(mem_node_t));
if(!p)goto err;
p->data = malloc(size + sizeof(u_int8_t));
if(!p->data)
{
free(p);
goto err;
}
ptype = p->data;
*ptype = type;
//p->type = type;
p->next = NULL;
p->pre = NULL;
if(!plist->list)
{
plist->list = p;
plist->ptr = p;
continue;
}
p->next = plist->list->next;
plist->list->next = p;
p->pre = plist->list;
if(p->next) p->next->pre = p;
}
while(plist->ptr->next) plist->ptr = plist->ptr->next;
plist->valid = 1;
if(print_msg) printk("init %d nodes of type %u success\n", length, type);
return 1;
err:
while(plist->list)
{
mem_node_t * p = plist->list;
plist->list = plist->list->next;
if(p)
{
if(p->data) free(p->data);
free(p);
}
}
mem_list[type].valid = 0;
mem_list[type].type = 0;
mem_list[type].list = NULL;
mem_list[type].ptr = NULL;
return 0;
}
void clean_mem_list(void)
{
int num = 0;
int left = -1;
int i = 0;
u_int8_t type;
for (i = 0; i < MAX_MEM_LIST; i++)
{
mem_list_t * plist = &mem_list[i];
if ( !plist->valid ) continue;
plist->valid = 0;
type = plist->type;
num = 0;
while(plist->list)
{
mem_node_t * p = plist->list;
if(p == plist->ptr) left = 0;
plist->list = plist->list->next;
if(p)
{
num++;
if(left >= 0) left++;
if(p->data) free(p->data);
free(p);
}
}
if(print_msg)
printk("free %d mem node(s) of type %u success, %d node(s) being used now\n",
num, type, left - 1);
}
}
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头文件head.h
#ifndef _HEAD_H_
#define _HEAD_H_
#ifdef __KERNEL__
#define malloc(a) kmalloc(a,GFP_ATOMIC)
#define free(a) kfree(a)
#endif
extern u_int8_t * new_mem_node(u_int8_t type);
extern void free_mem_node( u_int8_t * addr);
extern int init_mem_list ( u_int8_t type, int size, int length);
extern void clean_mem_list(void);
#endif
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目前没有在运行过程中做动态的reallocate,也就是说new失败时,就需要淘汰已有节点,主动free了
整个的存储图示意图如下:
[ 本帖最后由 duanjigang 于 2010-1-13 10:55 编辑 ] |
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