嵌入式

Linux线程池使用实例

2019-07-13 00:48发布

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struct job { void* (*callback_function)(void *arg); //线程回调函数 void *arg; //回调函数参数 struct job *next; }; struct threadpool { int thread_num; //线程池中开启线程的个数 int queue_max_num; //队列中最大job的个数 struct job *head; //指向job的头指针 struct job *tail; //指向job的尾指针 pthread_t *pthreads; //线程池中所有线程的pthread_t pthread_mutex_t mutex; //互斥信号量 pthread_cond_t queue_empty; //队列为空的条件变量 pthread_cond_t queue_not_empty; //队列不为空的条件变量 pthread_cond_t queue_not_full; //队列不为满的条件变量 int queue_cur_num; //队列当前的job个数 int queue_close; //队列是否已经关闭 int pool_close; //线程池是否已经关闭 }; //================================================================================================ //函数名： threadpool_init //函数描述： 初始化线程池 //输入： [in] thread_num 线程池开启的线程个数 // [in] queue_max_num 队列的最大job个数 //输出： 无 //返回： 成功：线程池地址 失败：NULL //================================================================================================ struct threadpool* threadpool_init(int thread_num, int queue_max_num); //================================================================================================ //函数名： threadpool_add_job //函数描述： 向线程池中添加任务 //输入： [in] pool 线程池地址 // [in] callback_function 回调函数 // [in] arg 回调函数参数 //输出： 无 //返回： 成功：0 失败：-1 //================================================================================================ int threadpool_add_job(struct threadpool *pool, void* (*callback_function)(void *arg), void *arg); //================================================================================================ //函数名： threadpool_destroy //函数描述： 销毁线程池 //输入： [in] pool 线程池地址 //输出： 无 //返回： 成功：0 失败：-1 //================================================================================================ int threadpool_destroy(struct threadpool *pool); //================================================================================================ //函数名： threadpool_function //函数描述： 线程池中线程函数 //输入： [in] arg 线程池地址 //输出： 无 //返回： 无 //================================================================================================ void* threadpool_function(void* arg); #include "threadpool.h" struct threadpool* threadpool_init(int thread_num, int queue_max_num) { struct threadpool *pool = NULL; do { pool = malloc(sizeof(struct threadpool)); if (NULL == pool) { printf("failed to malloc threadpool! "); break; } pool->thread_num = thread_num; pool->queue_max_num = queue_max_num; pool->queue_cur_num = 0; pool->head = NULL; pool->tail = NULL; if (pthread_mutex_init(&(pool->mutex), NULL)) { printf("failed to init mutex! "); break; } if (pthread_cond_init(&(pool->queue_empty), NULL)) { printf("failed to init queue_empty! "); break; } if (pthread_cond_init(&(pool->queue_not_empty), NULL)) { printf("failed to init queue_not_empty! "); break; } if (pthread_cond_init(&(pool->queue_not_full), NULL)) { printf("failed to init queue_not_full! "); break; } pool->pthreads = malloc(sizeof(pthread_t) * thread_num); if (NULL == pool->pthreads) { printf("failed to malloc pthreads! "); break; } pool->queue_close = 0; pool->pool_close = 0; int i; for (i = 0; i < pool->thread_num; ++i) { pthread_create(&(pool->pthreads[i]), NULL, threadpool_function, (void *)pool); } return pool; } while (0); return NULL; } int threadpool_add_job(struct threadpool* pool, void* (*callback_function)(void *arg), void *arg) { assert(pool != NULL); assert(callback_function != NULL); assert(arg != NULL); pthread_mutex_lock(&(pool->mutex)); while ((pool->queue_cur_num == pool->queue_max_num) && !(pool->queue_close || pool->pool_close)) { pthread_cond_wait(&(pool->queue_not_full), &(pool->mutex)); //队列满的时候就等待 } if (pool->queue_close || pool->pool_close) //队列关闭或者线程池关闭就退出 { pthread_mutex_unlock(&(pool->mutex)); return -1; } struct job *pjob =(struct job*) malloc(sizeof(struct job)); if (NULL == pjob) { pthread_mutex_unlock(&(pool->mutex)); return -1; } pjob->callback_function = callback_function; pjob->arg = arg; pjob->next = NULL; if (pool->head == NULL) { pool->head = pool->tail = pjob; pthread_cond_broadcast(&(pool->queue_not_empty)); //队列空的时候，有任务来时就通知线程池中的线程：队列非空 } else { pool->tail->next = pjob; pool->tail = pjob; } pool->queue_cur_num++; pthread_mutex_unlock(&(pool->mutex)); return 0; } void* threadpool_function(void* arg) { struct threadpool *pool = (struct threadpool*)arg; struct job *pjob = NULL; while (1) //死循环 { pthread_mutex_lock(&(pool->mutex)); while ((pool->queue_cur_num == 0) && !pool->pool_close) //队列为空时，就等待队列非空 { pthread_cond_wait(&(pool->queue_not_empty), &(pool->mutex)); } if (pool->pool_close) //线程池关闭，线程就退出 { pthread_mutex_unlock(&(pool->mutex)); pthread_exit(NULL); } pool->queue_cur_num--; pjob = pool->head; if (pool->queue_cur_num == 0) { pool->head = pool->tail = NULL; } else { pool->head = pjob->next; } if (pool->queue_cur_num == 0) { pthread_cond_signal(&(pool->queue_empty)); //队列为空，就可以通知threadpool_destroy函数，销毁线程函数 } if (pool->queue_cur_num == pool->queue_max_num - 1) { pthread_cond_broadcast(&(pool->queue_not_full)); //队列非满，就可以通知threadpool_add_job函数，添加新任务 } pthread_mutex_unlock(&(pool->mutex)); (*(pjob->callback_function))(pjob->arg); //线程真正要做的工作，回调函数的调用 free(pjob); pjob = NULL; } } int threadpool_destroy(struct threadpool *pool) { assert(pool != NULL); pthread_mutex_lock(&(pool->mutex)); if (pool->queue_close || pool->pool_close) //线程池已经退出了，就直接返回 { pthread_mutex_unlock(&(pool->mutex)); return -1; } pool->queue_close = 1; //置队列关闭标志 while (pool->queue_cur_num != 0) { pthread_cond_wait(&(pool->queue_empty), &(pool->mutex)); //等待队列为空 } pool->pool_close = 1; //置线程池关闭标志 pthread_mutex_unlock(&(pool->mutex)); pthread_cond_broadcast(&(pool->queue_not_empty)); //唤醒线程池中正在阻塞的线程 pthread_cond_broadcast(&(pool->queue_not_full)); //唤醒添加任务的threadpool_add_job函数 int i; for (i = 0; i < pool->thread_num; ++i) { pthread_join(pool->pthreads[i], NULL); //等待线程池的所有线程执行完毕 } pthread_mutex_destroy(&(pool->mutex)); //清理资源 pthread_cond_destroy(&(pool->queue_empty)); pthread_cond_destroy(&(pool->queue_not_empty)); pthread_cond_destroy(&(pool->queue_not_full)); free(pool->pthreads); struct job *p; while (pool->head != NULL) { p = pool->head; pool->head = p->next; free(p); } free(pool); return 0; }复制代码main.c#include "threadpool.h" void* work(void* arg) { char *p = (char*) arg; printf("threadpool callback fuction : %s. ", p); sleep(1); } int main(void) { struct threadpool *pool = threadpool_init(10, 20); threadpool_add_job(pool, work, "1"); threadpool_add_job(pool, work, "2"); threadpool_add_job(pool, work, "3"); threadpool_add_job(pool, work, "4"); threadpool_add_job(pool, work, "5"); threadpool_add_job(pool, work, "6"); threadpool_add_job(pool, work, "7"); threadpool_add_job(pool, work, "8"); threadpool_add_job(pool, work, "9"); threadpool_add_job(pool, work, "10"); threadpool_add_job(pool, work, "11"); threadpool_add_job(pool, work, "12"); threadpool_add_job(pool, work, "13"); threadpool_add_job(pool, work, "14"); threadpool_add_job(pool, work, "15"); threadpool_add_job(pool, work, "16"); threadpool_add_job(pool, work, "17"); threadpool_add_job(pool, work, "18"); threadpool_add_job(pool, work, "19"); threadpool_add_job(pool, work, "20"); threadpool_add_job(pool, work, "21"); threadpool_add_job(pool, work, "22"); threadpool_add_job(pool, work, "23"); threadpool_add_job(pool, work, "24"); threadpool_add_job(pool, work, "25"); threadpool_add_job(pool, work, "26"); threadpool_add_job(pool, work, "27"); threadpool_add_job(pool, work, "28"); threadpool_add_job(pool, work, "29"); threadpool_add_job(pool, work, "30"); threadpool_add_job(pool, work, "31"); threadpool_add_job(pool, work, "32"); threadpool_add_job(pool, work, "33"); threadpool_add_job(pool, work, "34"); threadpool_add_job(pool, work, "35"); threadpool_add_job(pool, work, "36"); threadpool_add_job(pool, work, "37"); threadpool_add_job(pool, work, "38"); threadpool_add_job(pool, work, "39"); threadpool_add_job(pool, work, "40"); sleep(5); threadpool_destroy(pool); return 0; }

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