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我正在阅读 Peter B. Galvin 的操作系统概念中的临界区问题。
根据它
1) 进度 is :如果没有进程在其临界区中执行,而某些进程希望进入其临界区,则只有那些未在其剩余部分中执行的进程才能参与决定下一个将进入其临界区的进程,并且此选择不能无限期推迟。
和
2)有界等待是 :在一个进程请求进入其临界区之后,在该请求被批准之前,允许其他进程进入其临界区的次数存在界限或限制。
我不明白作者想在这两种情况下说什么。
您能否通过给出与此定义相关的适当示例来让我理解。
谢谢你。
最佳答案
首先,让我介绍一些术语。临界区 (CS) 是一系列指令,最多可以同时由一个进程执行。使用临界区时,代码可以分解为以下部分:
// Some arbitrary code (such as initialization).
EnterCriticalSection(cs);
// The code that constitutes the CS.
// Only one process can be executing this code at the same time.
LeaveCriticalSection(cs);
// Some arbitrary code. This is called the remainder section.
Progress: If no process is executing in its critical section and some processes wish to enter their critical sections, then only those processes that are not executing in their remainder section can participate in deciding which will enter its critical section next, and this selection cannot be postponed indefinitely.
If no process is executing in its critical section
and some processes wish to enter their critical sections
then only those processes that are not executing in their remainder section
can participate in deciding which will enter its critical section next,
and this selection cannot be postponed indefinitely.
Bounded waiting: There exists a bound, or limit, on the number of times other processes are allowed to enter their critical sections after a process has made request to enter its critical section and before that request is granted.
after a process has made request to enter its critical section and before that request is granted.
There exists a bound, or limit, on the number of times other processes are allowed to enter their critical sections
关于operating-system - 临界区的进度和有界等待是什么?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/33143779/
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