如果两个线程被锁定在锁上,那么您如何选择该锁呢?
例如,thread1
调用mutex_lock(aMut)
但aMut
已被锁定,因此thread1
会被阻止。随之而来的是thread2
,它在aMut
上调用互斥锁并阻塞。如何确保将aMut
赋予thread2
?
这是我的尝试不起作用
/*global variables*/
pthread_mutex_t aMut = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t cond_var = PTHREAD_COND_INITIIALIZER;
pthread_cond_t changeNumPrior = PTHREAD_COND_INITIIALIZER;
int highPriorityThreads = 0;
/*function that is passed to pthread_create()*/
void* functionThatIsPassedToPthreadCreate(void* arg)
{
bool highPriority = false;
if(arg->someConditionIsMet)
{
highPriorityThreads++;
highPriority = true;
}
pthread_mutex_lock(&changeNumPrior);
while(!highPriority && highPriorities > 0)//this doesn't work
{
pthread_cond_wait(&cond_var, &changeNumPrior);
}
pthread_mutex_unlock(&changeNumPrior);
pthread_mutex_lock(&aMut);//if this blocks, by the time this mutex is aquired, there now may be high priority threads
//code that requires exclusive access to shared resource protected by aMut
pthread_mutex_unlock(&aMut);
pthread_cond_signal(&cond_var);
}
最佳答案
只是说“现在我要安排此任务,现在要安排这个任务”是不可能的,但是某些线程库允许设置任务的优先级,因此在计划时将受到青睐。
对于pthread,可以使用pthread_getschedparam
进行此操作。
关于c - 提供互斥锁以更正线程,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/26583261/