内存池

线程从内存池中获得内存块与释放内存块 更多...

线程从内存池中获得内存块与释放内存块

源码

/*
 * Copyright (c) 2006-2018, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date Author Notes
 * 2018-08-24 yangjie the first version
 */

/*
 * 程序清单：内存池例程
 *
 * 这个程序会创建一个静态的内存池对象，2个动态线程。
 * 一个线程会试图从内存池中获得内存块，另一个线程释放内存块
 * 内存块
 */
#include <rtthread.h>

static rt_uint8_t *ptr[50];
static rt_uint8_t mempool[4096];
static struct rt_mempool mp;

#define THREAD_PRIORITY 25
#define THREAD_STACK_SIZE 512
#define THREAD_TIMESLICE 5

/* 指向线程控制块的指针 */
static rt_thread_t tid1 = RT_NULL;
static rt_thread_t tid2 = RT_NULL;

/* 线程1入口 */
static void thread1_mp_alloc(void *parameter)
{
 int i;
 for (i = 0 ; i < 50 ; i++)
 {
 if (ptr[i] == RT_NULL)
 {
 /* 试图申请内存块50次，当申请不到内存块时，
 线程1挂起，转至线程2运行 */
 ptr[i] = rt_mp_alloc(&mp, RT_WAITING_FOREVER);
 if (ptr[i] != RT_NULL)
 rt_kprintf("allocate No.%d\n", i);
 }
 }
}

/* 线程2入口，线程2的优先级比线程1低，应该线程1先获得执行。*/
static void thread2_mp_release(void *parameter)
{
 int i;

 rt_kprintf("thread2 try to release block\n");
 for (i = 0; i < 50 ; i++)
 {
 /* 释放所有分配成功的内存块 */
 if (ptr[i] != RT_NULL)
 {
 rt_kprintf("release block %d\n", i);
 rt_mp_free(ptr[i]);
 ptr[i] = RT_NULL;
 }
 }
}

int mempool_sample(void)
{
 int i;
 for (i = 0; i < 50; i ++) ptr[i] = RT_NULL;

 /* 初始化内存池对象 */
 rt_mp_init(&mp, "mp1", &mempool[0], sizeof(mempool), 80);

 /* 创建线程1：申请内存池 */
 tid1 = rt_thread_create("thread1", thread1_mp_alloc, RT_NULL,
 THREAD_STACK_SIZE,
 THREAD_PRIORITY, THREAD_TIMESLICE);
 if (tid1 != RT_NULL)
 rt_thread_startup(tid1);

 /* 创建线程2：释放内存池*/
 tid2 = rt_thread_create("thread2", thread2_mp_release, RT_NULL,
 THREAD_STACK_SIZE,
 THREAD_PRIORITY + 1, THREAD_TIMESLICE);
 if (tid2 != RT_NULL)
 rt_thread_startup(tid2);

 return 0;
}

/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(mempool_sample, mempool sample);