1. 什么是C++中的读写锁(read-write lock)? 读写锁(Read-Write Lock)是一种同步机制,用于管理对共享资源的访问。它允许多个线程同时读取共享资源,但在写入时,必须独占访问权,以确保数据的一致性和完整性。 2. 读写锁的工作原理和主要特点 工作原理: 读锁:当有线程需要读取共享资源时,它会尝试获取读锁。如...
ReentrantReadWriteLock, 可重入读写锁, 包含读锁与写锁,具体结构如下图: ReentrantReadWriteLock包含了很多内部类,其中最核心的为Sync、ReadLock、WriteLock Sync内部类 sync内部类是AQS的实现类,实现了共享锁、独占锁的获取与释放方法,同时将AQS中的state状态值拆分为高16位、低16位(分别代表读锁(共享锁)获取数...
因此, 分析读写锁ReentrantReadWriteLock,会发现它有个潜在的问题:读锁全完,写锁有望;写锁独占,读写全堵; 如果有线程正在读,写线程需要等待读线程释放锁后才能获取写锁,见前面Case《code演示LockDownGradingDemo》 即ReadWriteLock读的过程中不允许写,只有等待线程都释放了读锁,当前线程才能获取 写锁, 也就是写...
import java.util.HashMap;import java.util.Map;import java.util.concurrent.TimeUnit;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;import java.util.concurrent.locks.ReentrantReadWriteLock;class MyResource{Map<String,String> map = new HashMap<>();//===Reentran...
代码spinlock.cpp: #include<atomic>#include<cassert>#defineSPIN_LOCK_UNLOCK 0#defineSPIN_LOCK_WRITE_LOCK -1usingstd::atomic;usingstd::atomic_int;usingstd::atomic_store_explicit;usingstd::atomic_load_explicit;usingstd::atomic_compare_exchange_weak_explicit;usingstd::memory_order_relaxed;usingstd:...
1.ReentrantReadWriteLock 读写锁定义: 多个读线程访问,或者被一个写线程访问,但是不能同时存在读写线程。 意义和特点: 读写锁ReentrantReadWriteLock并不是真正意义上的读写分离,它只允许读读共存,而读写和写写依然是互斥的, 大多实际场景是“读/读”线程间并不存在互斥关系,只有"读/写"线程或"写/写"线程间...
1333 int (*flock) (struct file *, int, struct file_lock *); 1334 ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int); 1335 ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned i nt);...
引用cppreference 的介绍:The mutex class is a synchronization primitive that can be used to protect shared data from being simultaneously accessed by multiple threads.Mutex 1直接操作 mutex,即直接调用 mutex 的 lock / unlock 函数。#include <iostream> #include <mutex> #include <thread> #include <...
So we need to let serial-read lock be different lock with serial-write lock . I Write such Serial, it can work well : https://github.com/jeckypei/mbedosBase/blob/master/develop/driver/serial/BetterSerial.cpp Issue request type [ ] Question [ ] Enhancement [ ] Bugci...
https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/locks/ReadWriteLock.html 基本上,您的loadIds应该在继续操作之前获得write-lock。如果成功,它立即获取锁并继续计算;否则它会阻塞相应的thread,直到获得锁或抛出InterruptedException。 另一方面,getIds方法应该获取read-lock。当前thread立即获得锁(如果...