Ucore中使用信号量和管程解决理发师问题

barber_sync.c

#include <stdio.h>
#include <proc.h>
#include <sem.h>
#include <monitor.h>
#include <assert.h>

#define Chair 5
#define SLEEP_TIME 4

//----------理发师问题 使用信号量解法

semaphore_t mutex; //临界区互斥
semaphore_t chairs;//等候椅一般信号量，可用椅子数
semaphore_t barber;//理发师
int waiting_sem; //正在等候的顾客数量
bool close_sem;

int manager_using_semaphore(void *arg){
    do_sleep(500);

    down(&mutex);
    close_sem = 1;  //打烊了
    up(&chairs); //如果理发师还在睡觉，叫醒理发师
    up(&mutex);
}

int barber_using_semaphore(void *arg) //理发师，只有一个理发师进程运行此函数
{

    while(1){  
        if(waiting_sem == 0)
            cprintf("There's no customer, I will sleep\n"); 
        
        down(&chairs); //找一位正在等候的顾客来理发，如果没有顾客则一直睡觉
        up(&barber); //开始理发
        do_sleep(SLEEP_TIME); //正在理发
        if (close_sem)
            break;
        
    }

    //收尾。禁止在进来，如果椅子上还有人等，则替他们理发
    {
        int left = Chair;
        while(left-- > 0){
            up(&barber); //开始理发
            do_sleep(SLEEP_TIME); //正在理发
        }
    }
    cprintf("Today's work is over\n");
    return 0;
}

int customer_using_semaphore(void *arg){
    int i = (int)arg; //顾客ID

    if(waiting_sem == Chair){
        cprintf("So much customers, I No.%d will leave\n", i);
    }else{

        down(&mutex);
        up(&chairs);
        cprintf("I am No.%d customer, I'm in. There are %d other  people except me\n",i, waiting_sem);
        waiting_sem ++;
        up(&mutex);

        down(&barber);  //等待理发
        down(&mutex); //进入临界区
        waiting_sem --;   //等候顾客数减1
        up(&mutex);

        cprintf("I am No.%d customer, I'm getting a haircut\n",i);
        return 0;
    }
    return 0;
}

//------------管程解法--------

int waiting_mon;
bool close_mon = 0;
monitor_t mt, *mtb = &mt;

int manager_using_monitor(void *arg){
    do_sleep(500);

    down(&(mtb->mutex));
    //--------into routine in monitor--------------
    close_mon = 1;  //打烊了
    cond_signal(&(mtb->cv[0])); //如果理发师还在睡觉，叫醒理发师
    //--------leave routine in monitor--------------
    if(mtb->next_count>0)
        up(&(mtb->next));
    else
        up(&(mtb->mutex));
}

//-------------barber using monitor ------------
int barber_using_monitor(void *arg){

    while(1){
        down(&(mtb->mutex));
        //--------into routine in monitor--------------
        if (waiting_mon == 0){
            cprintf("There's no customer, I will sleep\n"); 
            cond_wait(&(mtb->cv[0]));  //等待顾客进来
        }
        cond_signal(&(mtb->cv[1])); //告诉顾客
        //--------leave routine in monitor--------------
        if(mtb->next_count>0)
            up(&(mtb->next));
        else
            up(&(mtb->mutex));
        //理发
        do_sleep(SLEEP_TIME);
        if (close_mon){
            break;
        }
    }
    
    //收尾，如果椅子上还有人等，则替他们理发
    {
        int left = Chair;   //最多有这么多人在等
        while(left-- > 0){ 
            down(&(mtb->mutex));
            //--------into routine in monitor--------------
            cond_signal(&(mtb->cv[1])); //告诉顾客
            //--------leave routine in monitor--------------
            if(mtb->next_count>0)
                up(&(mtb->next));
            else
                up(&(mtb->mutex));
            //理发
            do_sleep(SLEEP_TIME);
        }
    }
    cprintf("Today's work is over\n");
    return 0;
}

int customer_using_monitor(void *arg){
    int i = (int)arg; //顾客ID
    down(&(mtb->mutex));
    //--------into routine in monitor--------------
    if(close_mon){
        cprintf("Closed, I No.%d will leave\n", i);
    }else if (waiting_mon == Chair){
        cprintf("So much customers, I No.%d will leave\n", i);
    }else{
        waiting_mon ++;
        cprintf("I am No.%d customer, I'm in. There are %d people\n",i, waiting_mon);
        cond_signal(&(mtb->cv[0])); //告诉理发师有人进来了
        cond_wait(&(mtb->cv[1])); //等理发师
        waiting_mon --;
        cprintf("I am No.%d customer, I'm getting a haircut\n",i);
    }
    //--------leave routine in monitor--------------
    if(mtb->next_count>0)
        up(&(mtb->next));
    else
        up(&(mtb->mutex));

}


//-------------
void check_barber_sync(void){

    int i = 0, pid = 0;
    //check semaphore
    sem_init(&mutex,1);
    sem_init(&barber,0);
    sem_init(&chairs,0);
    waiting_sem = 0;
    close_sem = 0;

    pid = kernel_thread(manager_using_semaphore, (void *)0, 0);
    if (pid <= 0) {
        panic("create manage_using_semaphore failed.\n");
    }
    pid = kernel_thread(barber_using_semaphore, (void *)0, 0);
    if (pid <= 0) {
        panic("create barber_using_semaphore failed.\n");
    }

    for(i = 0; i < 30; i++) { 
        do_sleep(3);
        pid=kernel_thread(customer_using_semaphore,(void *)i,0);//创建顾客线程
        if(pid<=0) { 
            cprintf("Customer is not created.\n"); 
        }
    }

    do_sleep(45);
    for(; i < 60; i++) { 
        do_sleep(5);
        pid=kernel_thread(customer_using_semaphore,(void *)i,0);//创建顾客线程
        if(pid<=0) { 
            cprintf("Customer is not created.\n"); 
        }
    }
  
    //check condition variable
    monitor_init(&mt, 2);
    waiting_mon = 0;
    close_mon = 0;

    pid = kernel_thread(manager_using_monitor, (void *)0, 0);
    if (pid <= 0) {
        panic("create manage_using_semaphore failed.\n");
    }

    pid = kernel_thread(barber_using_monitor, (void *)0, 0);
    if (pid <= 0) {
        panic("create barber_using_semaphore failed.\n");
    }
    for(i = 0; i < 30; i++) { 
        do_sleep(3);
        pid=kernel_thread(customer_using_monitor,(void *)i,0);//创建顾客线程
        if(pid<=0) { 
            cprintf("Customer is not created.\n"); 
        }
    }

    do_sleep(45);
    for(; i < 60; i++) { 
        do_sleep(5);
        pid=kernel_thread(customer_using_monitor,(void *)i,0);//创建顾客线程
        if(pid<=0) { 
            cprintf("Customer is not created.\n"); 
        }
    }

}