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Apache学习示例父子进程管理                

下面是Apache1.3版本里进程管理的示意代码，请大家参考：
//演示分配生成子进程

make_child(slot)
{
[...]
pid = fork();//分配
if ( pid == 0 )
{
/* Child Process: worker */
scoreboard[slot].status = STARTING;
child_main(slot);//子进程执行
exit(0);
}
[...]
scoreboard[i].pid = pid;//修改记分牌
}

//演示对子进程管理

manage_worker_pool()
{
[...]
scoreboard = create_scoreboard();//创建记分牌
/* create workers 预分配一些子进程*/
 for (i = 0 ; i < to_start ; ++i )
{
make_child(i);
}

//修改没有和实际进程对应的记分牌条目状态为死亡状态

for (i = to_start ; i < limit ; ++i )
{
scoreboard[i].status = DEAD;
}
/* Control Loop 控制循环*/
while(!shutdown)
{
/* wait for termination signal or let some time pass 等待结束信号或者让时间过去*/
pid = wait_or_timeout();
if ( pid != 0 )
{
/* replace dead worker 替换死去的子进程*/
slot = find_child_by_pid(pid);
make_child(slot);
}
else
{
/* check number of workers 检查子进程数目*/
16
idle_count = 0;
for (i = 0 ; i < limit ; ++i )
{
if (scoreboard[i].status == IDLE)
{
idle_count++;
to_kill = i;
}
if (scoreboard[i].status == DEAD)
free_slot = i;
}
//如果空闲的不够，则分配
if (idle_count < min_idle)
{
make_child(free_slot);
}
//如果空闲的多了，则用信号释放
if (idle_count > max_idle)
{
kill(scoreboard[to_kill].pid);
scoreboard[to_kill].status = DEAD;
}
}
/* while(!shutdown) */
/* Terminate server 结束时，把所有子进程都释放了*/
for (i = 0 ; i < limit ; ++i )
{
if (scoreboard[i].status != DEAD)
kill(scoreboard[i].pid);
}
}