Linux_线程池
作者：互联网
/*任务*/
typedef struct {
void *(*function)(void *);
void *arg;
} threadpool_task_t;
/*线程池管理*/
struct threadpool_t{
pthread_mutex_t lock; /* 锁住整个结构体 */
pthread_mutex_t thread_counter; /* 用于使用忙线程数时的锁 */
pthread_cond_t queue_not_full; /* 条件变量，任务队列不为满 */
pthread_cond_t queue_not_empty; /* 任务队列不为空 */
pthread_t *threads; /* 存放线程的tid,实际上就是管理了线 数组 */
pthread_t admin_tid; /* 管理者线程tid */
threadpool_task_t *task_queue; /* 任务队列 */
/*线程池信息*/
int min_thr_num; /* 线程池中最小线程数 */
int max_thr_num; /* 线程池中最大线程数 */
int live_thr_num; /* 线程池中存活的线程数 */
int busy_thr_num; /* 忙线程，正在工作的线程 */
int wait_exit_thr_num; /* 需要销毁的线程数 */
/*任务队列信息*/
int queue_front; /* 队头 */
int queue_rear; /* 队尾 */
int queue_size;
/* 存在的任务数 */
int queue_max_size; /* 队列能容纳的最大任务数 */
/*线程池状态*/
int shutdown; /* true为关闭 */
};
**/*创建线程池*/**
threadpool_t * threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size)
{ /* 最小线程数 最大线程数 最大任务数*/
int i;
threadpool_t *pool = NULL;
do
{
/* 线程池空间开辟 */
if ((pool=(threadpool_t *)malloc(sizeof(threadpool_t))) == NULL)
{
printf("malloc threadpool false; \n");
break;
}
/*信息初始化*/
pool->min_thr_num = min_thr_num;
pool->max_thr_num = max_thr_num;
pool->busy_thr_num = 0;
pool->live_thr_num = min_thr_num;
pool->wait_exit_thr_num = 0;
pool->queue_front = 0;
pool->queue_rear = 0;
pool->queue_size = 0;
pool->queue_max_size = queue_max_size;
pool->shutdown = false;
/* 根据最大线程数，给工作线程数组开空间，清0 */
pool->threads = (pthread_t *)malloc(sizeof(pthread_t)*max_thr_num);
if (pool->threads == NULL)
{
printf("malloc threads false;\n");
break;
}
memset(pool->threads, 0, sizeof(pthread_t)*max_thr_num);
/* 队列开空间 */
pool->task_queue =
(threadpool_task_t *)malloc(sizeof(threadpool_task_t)*queue_max_size);
if (pool->task_queue == NULL)
{
printf("malloc task queue false;\n");
break;
}
/* 初始化互斥锁和条件变量 */
if ( pthread_mutex_init(&(pool->lock), NULL) != 0 ||
pthread_mutex_init(&(pool->thread_counter), NULL) !=0 ||
pthread_cond_init(&(pool->queue_not_empty), NULL) !=0 ||
pthread_cond_init(&(pool->queue_not_full), NULL) !=0)
{
printf("init lock or cond false;\n");
break;
}
/* 启动min_thr_num个工作线程 */
for (i=0; i<min_thr_num; i++)
{
/* pool指向当前线程池 threadpool_thread函数在后面讲解 */
pthread_create(&(pool->threads[i]), NULL, threadpool_thread, (void *)pool);
printf("start thread 0x%x... \n", (unsigned int)pool->threads[i]);
}
/* 管理者线程 admin_thread函数在后面讲解 */
pthread_create(&(pool->admin_tid), NULL, admin_thread, (void *)pool);
return pool;
} while(0);
/* 释放pool的空间 */
threadpool_free(pool);
return NULL;
}
/*工作线程*/
void * threadpool_thread(void *threadpool)
{
threadpool_t *pool = (threadpool_t *)threadpool;
threadpool_task_t task;
while (true)
{
pthread_mutex_lock(&(pool->lock));
/* 无任务则阻塞在 “任务队列不为空” 上，有任务则跳出 */
while ((pool->queue_size == 0) && (!pool->shutdown))
{
printf("thread 0x%x is waiting \n", (unsigned int)pthread_self());
pthread_cond_wait(&(pool->queue_not_empty), &(pool->lock));
/* 判断是否需要清除线程,自杀功能 */
if (pool->wait_exit_thr_num > 0)
{
pool->wait_exit_thr_num--;
/* 判断线程池中的线程数是否大于最小线程数，是则结束当前线程 */
if (pool->live_thr_num > pool->min_thr_num)
{
printf("thread 0x%x is exiting \n", (unsigned int)pthread_self());
pool->live_thr_num--;
pthread_mutex_unlock(&(pool->lock));
pthread_exit(NULL);//结束线程
}
}
}
/* 线程池开关状态 */
if (pool->shutdown) //关闭线程池
{
pthread_mutex_unlock(&(pool->lock));
printf("thread 0x%x is exiting \n", (unsigned int)pthread_self());
pthread_exit(NULL); //线程自己结束自己
}
//否则该线程可以拿出任务
task.function = pool->task_queue[pool->queue_front].function; //出队操作
task.arg = pool->task_queue[pool->queue_front].arg;
pool->queue_front = (pool->queue_front + 1) % pool->queue_max_size; //环型结构
pool->queue_size--;
//通知可以添加新任务
pthread_cond_broadcast(&(pool->queue_not_full));
//释放线程锁
pthread_mutex_unlock(&(pool->lock));
//执行刚才取出的任务
printf("thread 0x%x start working \n", (unsigned int)pthread_self());
pthread_mutex_lock(&(pool->thread_counter)); //锁住忙线程变量
pool->busy_thr_num++;
pthread_mutex_unlock(&(pool->thread_counter));
(*(task.function))(task.arg); //执行任务
//任务结束处理
printf("thread 0x%x end working \n", (unsigned int)pthread_self());
pthread_mutex_lock(&(pool->thread_counter));
pool->busy_thr_num--;
pthread_mutex_unlock(&(pool->thread_counter));
}
pthread_exit(NULL);
}
/*向线程池的任务队列中添加一个任务*/
int threadpool_add_task(threadpool_t *pool, void *(*function)(void *arg), void *arg)
{
pthread_mutex_lock(&(pool->lock));
/*如果队列满了,调用wait阻塞*/
while ((pool->queue_size == pool->queue_max_size) && (!pool->shutdown))
pthread_cond_wait(&(pool->queue_not_full), &(pool->lock));
/*如果线程池处于关闭状态*/
if (pool->shutdown)
{
pthread_mutex_unlock(&(pool->lock));
return -1;
}
/*清空工作线程的回调函数的参数arg*/
if (pool->task_queue[pool->queue_rear].arg != NULL)
{
free(pool->task_queue[pool->queue_rear].arg);
pool->task_queue[pool->queue_rear].arg = NULL;
}
/*添加任务到任务队列*/
pool->task_queue[pool->queue_rear].function = function;
pool->task_queue[pool->queue_rear].arg = arg;
pool->queue_rear = (pool->queue_rear + 1) % pool->queue_max_size; /* 逻辑环 */
pool->queue_size++;
/*添加完任务后,队列就不为空了,唤醒线程池中的一个线程*/
pthread_cond_signal(&(pool->queue_not_empty));
pthread_mutex_unlock(&(pool->lock));
return 0;
}
/*管理线程*/
void * admin_thread(void *threadpool)
{
int i;
threadpool_t *pool = (threadpool_t *)threadpool;
while (!pool->shutdown)
{
printf("admin -----------------\n");
sleep(DEFAULT_TIME); /*隔一段时间再管理*/
pthread_mutex_lock(&(pool->lock)); /*加锁*/
int queue_size = pool->queue_size; /*任务数*/
int live_thr_num = pool->live_thr_num; /*存活的线程数*/
pthread_mutex_unlock(&(pool->lock)); /*解锁*/
pthread_mutex_lock(&(pool->thread_counter));
int busy_thr_num = pool->busy_thr_num; /*忙线程数*/
pthread_mutex_unlock(&(pool->thread_counter));
printf("admin busy live -%d--%d-\n", busy_thr_num, live_thr_num);
/*创建新线程 实际任务数量大于 最小正在等待的任务数量，存活线程数小于最大线程数*/
if (queue_size >= MIN_WAIT_TASK_NUM && live_thr_num <= pool->max_thr_num)
{
printf("admin add-----------\n");
pthread_mutex_lock(&(pool->lock));
int add=0;
/*一次增加 DEFAULT_THREAD_NUM 个线程*/
for (i=0; i<pool->max_thr_num && add<DEFAULT_THREAD_NUM
&& pool->live_thr_num < pool->max_thr_num; i++)
{
if (pool->threads[i] == 0 || !is_thread_alive(pool->threads[i]))
{
pthread_create(&(pool->threads[i]), NULL, threadpool_thread, (void *)pool);
add++;
pool->live_thr_num++;
printf("new thread -----------------------\n");
}
}
pthread_mutex_unlock(&(pool->lock));
}
/*销毁多余的线程 忙线程x2 都小于 存活线程，并且存活的大于最小线程数*/
if ((busy_thr_num*2) < live_thr_num && live_thr_num > pool->min_thr_num)
{
// printf("admin busy --%d--%d----\n", busy_thr_num, live_thr_num);
/*一次销毁DEFAULT_THREAD_NUM个线程*/
pthread_mutex_lock(&(pool->lock));
pool->wait_exit_thr_num = DEFAULT_THREAD_NUM;
pthread_mutex_unlock(&(pool->lock));
for (i=0; i<DEFAULT_THREAD_NUM; i++)
{
//通知正在处于空闲的线程，自杀
pthread_cond_signal(&(pool->queue_not_empty));
printf("admin cler --\n");
}
}
}
return NULL;
/*线程是否存活*/
int is_thread_alive(pthread_t tid)
{
int kill_rc = pthread_kill(tid, 0); //发送0号信号，测试是否存活
if (kill_rc == ESRCH) //线程不存在
{
return false;
}
return true;
}
/*释放线程池*/
int threadpool_free(threadpool_t *pool)
{
if (pool == NULL)
return -1;
if (pool->task_queue)
free(pool->task_queue);
if (pool->threads)
{
free(pool->threads);
pthread_mutex_lock(&(pool->lock)); /*先锁住再销毁*/
pthread_mutex_destroy(&(pool->lock));
pthread_mutex_lock(&(pool->thread_counter));
pthread_mutex_destroy(&(pool->thread_counter));
pthread_cond_destroy(&(pool->queue_not_empty));
pthread_cond_destroy(&(pool->queue_not_full));
}
free(pool);
pool = NULL;
return 0;
}
/*销毁线程池*/
int threadpool_destroy(threadpool_t *pool)
{
int i;
if (pool == NULL)
{
return -1;
}
pool->shutdown = true;
/*销毁管理者线程*/
pthread_join(pool->admin_tid, NULL);
//通知所有线程去自杀(在自己领任务的过程中)
for (i=0; i<pool->live_thr_num; i++)
{
pthread_cond_broadcast(&(pool->queue_not_empty));
}
/*等待线程结束 先是pthread_exit 然后等待其结束*/
for (i=0; i<pool->live_thr_num; i++)
{
pthread_join(pool->threads[i], NULL);
}
threadpool_free(pool);
return 0;
}
/*
/* 线程池初始化，其管理者线程及工作线程都会启动 */
threadpool_t *thp = threadpool_create(10, 100, 100);
printf("threadpool init ... ... \n");
/* 接收到任务后添加 */
threadpool_add_task(thp, do_work, (void *)p);
// ... ...
/* 销毁 */
threadpool_destroy(thp)；
*/
标签：Linux,thr,queue,num,线程,pthread,pool 来源： https://www.cnblogs.com/Liutt1312/p/14693840.html