Question

我正在尝试实施睡眠理发师问题的解决方案。我为理发师编写了以下代码：

while(1){
sem_wait(semsid, mutex);
if(semctl(semsid, customer, GETVAL, 0) == 0){
  logg("...zzz...zzz...\n");
}

sem_signal(semsid, mutex);

sem_wait(semsid, customer);

sem_wait(semsid, isSomeoneCut_sem);
FIFO->isSomeoneCut = 1;
sem_signal(semsid, isSomeoneCut_sem);

sem_wait(semsid, mutex);      //blokujemy dostęp do kolejki
int* tmp = qpop(FIFO, addrFifo);
int pid = tmp[0];
int sem = tmp[1];
FIFO->customers--;
sem_signal(semsid, sem);
sem_signal(semsid, mutex);    //.odbblokowujemy kolejkę


cutHair(pid);
sem_wait(semsid, customerDone);   //razem kończymy strzyżenie
sem_signal(semsid, barberDone);

sem_wait(semsid, isSomeoneCut_sem);
FIFO->isSomeoneCut = 0;
sem_signal(semsid, isSomeoneCut_sem);
}

以下为客户：

sem_wait(semsid, mutex);
sem_wait(semsid, isSomeoneCut_sem);

if(qisFull(q)){    //queue is full, leaving
  logg("queue is FULL, leaving.\n");
  sem_signal(semsid, isSomeoneCut_sem);
  sem_signal(semsid, mutex);
  sleep(1);
  continue;
}
else if(qisEmpty(q) && q->isSomeoneCut == 0){
  logg("Nobody's waiting, waking the barber.\n");
}
else{
  q->customers++;
  logg("Taking a seat in waiting room.\n");
}

sem_signal(semsid, isSomeoneCut_sem);

int mysem = getSemInd(q);
semctl(semsid, mysem, SETVAL, 0);


qpush(q, addrFifo, getpid(), mysem);
sem_signal(semsid, mutex);
sem_signal(semsid, customer);

sem_wait(semsid, mysem);

getHaircut();

sem_signal(semsid, customerDone); //wspólnie kończymy strzyżenie
sem_wait(semsid, barberDone);

logg("I was cut and am leaving the shop.\n");

FIFO与标志，队列中的客户数量等一起保存在共享内存段中。当我运行程序时，我遇到了一个小问题： - 理发师不能立即设置标志是在醒来后的某人切断（有人可以打断他，例如再次唤醒他。如果您发现任何其他问题，请告诉我。提前谢谢！

在信号量上睡觉理发师FIFO（没有饥饿）

0 个答案: