头文件head.h
#ifndef __THREADPOOL_H_ #define __THREADPOOL_H_ typedef struct threadpool_t threadpool_t; /** * @function threadpool_create * @descCreates a threadpool_t object. * @param thr_num thread num * @param max_thr_num max thread size * @param queue_max_size size of the queue. * @return a newly created thread pool or NULL */ threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size); /** * @function threadpool_add * @desc add a new task in the queue of a thread pool * @param pool Thread pool to which add the task. * @param function Pointer to the function that will perform the task. * @param argument Argument to be passed to the function. * @return 0 if all goes well,else -1 */ int threadpool_add(threadpool_t *pool, void*(*function)(void *arg), void *arg); /** * @function threadpool_destroy * @desc Stops and destroys a thread pool. * @param pool Thread pool to destroy. * @return 0 if destory success else -1 */ int threadpool_destroy(threadpool_t *pool); /** * @desc get the thread num * @pool pool threadpool * @return # of the thread */ int threadpool_all_threadnum(threadpool_t *pool); /** * desc get the busy thread num * @param pool threadpool * return # of the busy thread */ int threadpool_busy_threadnum(threadpool_t *pool); #endif
main.c
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include "threadpool.h"
#define DEFAULT_TIME 10 /*10s检测一次*/
#define MIN_WAIT_TASK_NUM 10 /*如果queue_size > MIN_WAIT_TASK_NUM 添加新的线程到线程池*/
#define DEFAULT_THREAD_VARY 10 /*每次创建和销毁线程的个数*/
#define true 1
#define false 0
typedef struct {
void *(*function)(void *); /* 函数指针，回调函数 */
void *arg; /* 上面函数的参数 */
} threadpool_task_t; /* 各子线程任务结构体 */
/* 描述线程池相关信息 */
struct threadpool_t {
pthread_mutex_t lock; /* 用于锁住本结构体 */
pthread_mutex_t thread_counter; /* 记录忙状态线程个数de琐 -- busy_thr_num */
pthread_cond_t queue_not_full; /* 当任务队列满时，添加任务的线程阻塞，等待此条件变量 */
pthread_cond_t queue_not_empty; /* 任务队列里不为空时，通知等待任务的线程 */
pthread_t *threads; /* 存放线程池中每个线程的tid。数组 */
pthread_t adjust_tid; /* 存管理线程tid */
threadpool_task_t *task_queue; /* 任务队列 */
int min_thr_num; /* 线程池最小线程数 */
int max_thr_num; /* 线程池最大线程数 */
int live_thr_num; /* 当前存活线程个数 */
int busy_thr_num; /* 忙状态线程个数 */
int wait_exit_thr_num; /* 要销毁的线程个数 */
int queue_front; /* task_queue队头下标 */
int queue_rear; /* task_queue队尾下标 */
int queue_size; /* task_queue队中实际任务数 */
int queue_max_size; /* task_queue队列可容纳任务数上限 */
int shutdown; /* 标志位，线程池使用状态，true或false */
};
/**
* @function void *threadpool_thread(void *threadpool)
* @desc the worker thread
* @param threadpool the pool which own the thread
*/
void *threadpool_thread(void *threadpool);
/**
* @function void *adjust_thread(void *threadpool);
* @desc manager thread
* @param threadpool the threadpool
*/
void *adjust_thread(void *threadpool);
/**
* check a thread is alive
*/
int is_thread_alive(pthread_t tid);
int threadpool_free(threadpool_t *pool);
threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size)
{
int i;
threadpool_t *pool = NULL;
do {
if((pool = (threadpool_t *)malloc(sizeof(threadpool_t))) == NULL) {
printf("malloc threadpool fail");
break;/*跳出do while*/
}
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; /* 活着的线程数 初值=最小线程数 */
pool->queue_size = 0; /* 有0个产品 */
pool->queue_max_size = queue_max_size;
pool->queue_front = 0;
pool->queue_rear = 0;
pool->shutdown = false; /* 不关闭线程池 */
/* 根据最大线程上限数， 给工作线程数组开辟空间, 并清零 */
pool->threads = (pthread_t *)malloc(sizeof(pthread_t)*max_thr_num);
if (pool->threads == NULL) {
printf("malloc threads fail");
break;
}
memset(pool->threads, 0, sizeof(pthread_t)*max_thr_num);
/* 队列开辟空间 */
pool->task_queue = (threadpool_task_t *)malloc(sizeof(threadpool_task_t)*queue_max_size);
if (pool->task_queue == NULL) {
printf("malloc task_queue fail");
break;
}
/* 初始化互斥琐、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 the lock or cond fail");
break;
}
/* 启动 min_thr_num 个 work thread */
for (i = 0; i < min_thr_num; i++) {
pthread_create(&(pool->threads[i]), NULL, threadpool_thread, (void *)pool);/*pool指向当前线程池*/
printf("start thread 0x%x...
", (unsigned int)pool->threads[i]);
}
pthread_create(&(pool->adjust_tid), NULL, adjust_thread, (void *)pool);/* 启动管理者线程 */
return pool;
} while (0);
threadpool_free(pool); /* 前面代码调用失败时，释放poll存储空间 */
return NULL;
}
/* 向线程池中 添加一个任务 */
int threadpool_add(threadpool_t *pool, void*(*function)(void *arg), void *arg)
{
pthread_mutex_lock(&(pool->lock));
/* ==为真，队列已经满， 调wait阻塞 */
while ((pool->queue_size == pool->queue_max_size) && (!pool->shutdown)) {
pthread_cond_wait(&(pool->queue_not_full), &(pool->lock));
}
if (pool->shutdown) {
pthread_mutex_unlock(&(pool->lock));
}
/* 清空 工作线程 调用的回调函数 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里*/
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; /* 队尾指针移动, 模拟环形 */
pool->queue_size++;
/*添加完任务后，队列不为空，唤醒线程池中 等待处理任务的线程*/
pthread_cond_signal(&(pool->queue_not_empty));
pthread_mutex_unlock(&(pool->lock));
return 0;
}
/* 线程池中各个工作线程 */
void *threadpool_thread(void *threadpool)
{
threadpool_t *pool = (threadpool_t *)threadpool;
threadpool_task_t task;
while (true) {
/* Lock must be taken to wait on conditional variable */
/*刚创建出线程，等待任务队列里有任务，否则阻塞等待任务队列里有任务后再唤醒接收任务*/
pthread_mutex_lock(&(pool->lock));
/*queue_size == 0 说明没有任务，调 wait 阻塞在条件变量上, 若有任务，跳过该while*/
while ((pool->queue_size == 0) && (!pool->shutdown)) {
printf("thread 0x%x is waiting
", (unsigned int)pthread_self());
pthread_cond_wait(&(pool->queue_not_empty), &(pool->lock));
/*清除指定数目的空闲线程，如果要结束的线程个数大于0，结束线程*/
if (pool->wait_exit_thr_num > 0) {
pool->wait_exit_thr_num--;
/*如果线程池里线程个数大于最小值时可以结束当前线程*/
if (pool->live_thr_num > pool->min_thr_num) {
printf("thread 0x%x is exiting
", (unsigned int)pthread_self());
pool->live_thr_num--;
pthread_mutex_unlock(&(pool->lock));
pthread_exit(NULL);
}
}
}
/*如果指定了true，要关闭线程池里的每个线程，自行退出处理*/
if (pool->shutdown) {
pthread_mutex_unlock(&(pool->lock));
printf("thread 0x%x is exiting
", (unsigned int)pthread_self());
pthread_exit(NULL); /* 线程自行结束 */
}
/*从任务队列里获取任务, 是一个出队操作*/
task.function = pool->task_queue[pool->queue_front].function;
task.arg = pool->task_queue[pool->queue_front].arg;
pool->queue_front = (pool->queue_front + 1) % pool->queue_max_size; /* 出队，模拟环形队列 */
pool->queue_size--;
/*通知可以有新的任务添加进来*/
pthread_cond_broadcast(&(pool->queue_not_full));
/*任务取出后，立即将 线程池琐 释放*/
pthread_mutex_unlock(&(pool->lock));
/*执行任务*/
printf("thread 0x%x start working
", (unsigned int)pthread_self());
pthread_mutex_lock(&(pool->thread_counter)); /*忙状态线程数变量琐*/
pool->busy_thr_num++; /*忙状态线程数+1*/
pthread_mutex_unlock(&(pool->thread_counter));
(*(task.function))(task.arg); /*执行回调函数任务*/
//task.function(task.arg); /*执行回调函数任务*/
/*任务结束处理*/
printf("thread 0x%x end working
", (unsigned int)pthread_self());
pthread_mutex_lock(&(pool->thread_counter));
pool->busy_thr_num--; /*处理掉一个任务，忙状态数线程数-1*/
pthread_mutex_unlock(&(pool->thread_counter));
}
pthread_exit(NULL);
}
/* 管理线程 */
void *adjust_thread(void *threadpool)
{
int i;
threadpool_t *pool = (threadpool_t *)threadpool;
while (!pool->shutdown) {
sleep(DEFAULT_TIME); /*定时 对线程池管理*/
pthread_mutex_lock(&(pool->lock));
int queue_size = pool->queue_size; /* 关注 任务数 */
int live_thr_num = pool->live_thr_num; /* 存活 线程数 */
pthread_mutex_unlock(&(pool->lock));
pthread_mutex_lock(&(pool->thread_counter));
int busy_thr_num = pool->busy_thr_num; /* 忙着的线程数 */
pthread_mutex_unlock(&(pool->thread_counter));
/* 创建新线程 算法： 任务数大于最小线程池个数, 且存活的线程数少于最大线程个数时 如：30>=10 && 40<100*/
if (queue_size >= MIN_WAIT_TASK_NUM && live_thr_num < pool->max_thr_num) {
pthread_mutex_lock(&(pool->lock));
int add = 0;
/*一次增加 DEFAULT_THREAD 个线程*/
for (i = 0; i < pool->max_thr_num && add < DEFAULT_THREAD_VARY
&& 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++;
}
}
pthread_mutex_unlock(&(pool->lock));
}
/* 销毁多余的空闲线程 算法：忙线程X2 小于 存活的线程数 且 存活的线程数 大于 最小线程数时*/
if ((busy_thr_num * 2) < live_thr_num && live_thr_num > pool->min_thr_num) {
/* 一次销毁DEFAULT_THREAD个线程, 隨機10個即可 */
pthread_mutex_lock(&(pool->lock));
pool->wait_exit_thr_num = DEFAULT_THREAD_VARY; /* 要销毁的线程数 设置为10 */
pthread_mutex_unlock(&(pool->lock));
for (i = 0; i < DEFAULT_THREAD_VARY; i++) {
/* 通知处在空闲状态的线程, 他们会自行终止*/
pthread_cond_signal(&(pool->queue_not_empty));
}
}
}
return NULL;
}
int threadpool_destroy(threadpool_t *pool)
{
int i;
if (pool == NULL) {
return -1;
}
pool->shutdown = true;
/*先销毁管理线程*/
pthread_join(pool->adjust_tid, NULL);
for (i = 0; i < pool->live_thr_num; i++) {
/*通知所有的空闲线程*/
pthread_cond_broadcast(&(pool->queue_not_empty));
}
for (i = 0; i < pool->live_thr_num; i++) {
pthread_join(pool->threads[i], NULL);
}
threadpool_free(pool);
return 0;
}
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));
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;
}
int threadpool_all_threadnum(threadpool_t *pool)
{
int all_threadnum = -1;
pthread_mutex_lock(&(pool->lock));
all_threadnum = pool->live_thr_num;
pthread_mutex_unlock(&(pool->lock));
return all_threadnum;
}
int threadpool_busy_threadnum(threadpool_t *pool)
{
int busy_threadnum = -1;
pthread_mutex_lock(&(pool->thread_counter));
busy_threadnum = pool->busy_thr_num;
pthread_mutex_unlock(&(pool->thread_counter));
return busy_threadnum;
}
int is_thread_alive(pthread_t tid)
{
int kill_rc = pthread_kill(tid, 0); //发0号信号，测试线程是否存活
if (kill_rc == ESRCH) {
return false;
}
return true;
}
/*测试*/
#if 1
/* 线程池中的线程，模拟处理业务 */
void *process(void *arg)
{
printf("thread 0x%x working on task %d
",(unsigned int)pthread_self(),*(int *)arg);
sleep(1);
printf("task %d is end
",*(int *)arg);
return NULL;
}
int main(void)
{
/*threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size);*/
threadpool_t *thp = threadpool_create(3,100,100);/*创建线程池，池里最小3个线程，最大100，队列最大100*/
printf("pool inited");
//int *num = (int *)malloc(sizeof(int)*20);
int num[20], i;
for (i = 0; i < 20; i++) {
num[i]=i;
printf("add task %d
",i);
threadpool_add(thp, process, (void*)&num[i]); /* 向线程池中添加任务 */
}
sleep(10); /* 等子线程完成任务 */
threadpool_destroy(thp);
return 0;
}
学习版：https://www.cnblogs.com/cthon/p/9085026.html
通用版代码：https://www.cnblogs.com/cthon/p/9097007.html
难度升级版代码：https://www.cnblogs.com/cthon/p/9085623.html