Java5 already contains a read-write lock in the Java.util.concurrent package. Still, we should understand the rationale behind its implementation.
Java implementation of read/write locks (Read/write lock Java Implementation)
Read/write
Basic Introduction:
Read and write Lock: ReadwritelockIn a multi-threaded environment, reading and writing to the same data will involve thread-safety issues. For example, when one thread reads the data, another thread writes the data, which
Reentrantlock are exclusive locks that allow only one thread to access at the same time, while read-write locks allow multiple threads to access at the same time, but all read and other write threads are blocked while the write thread is accessing.
I. Introduction to read and write locksIn reality there is a scenario where read and write operations are done on shared resources, and write operations are not as frequent as read operations. There is no problem with multiple threads reading a
In this section, we describe the lock-related APIs provided in the go language. This includes mutexes and read-write locks. We described the mutex in the 6th chapter, but did not mention the read-write lock. Both of these locks are very common and
Read/write Lock (Read-write lock)A reviewIn some programs there are reader-writer problems, that is, access to some resources there are two possible situations, one is that access must be exclusive line, that is, the meaning of exclusivity, which is
1.1.1.three write lock downgrade for read-write lock applicationReentrantreadwritelock also features write-lock demotion, which has some relationship to reentrant sex. (1) you can downgrade to read lock when holding a write lock. (2) You cannot
1. What is read and write lock
It is possible to allow multiple read threads to access at the same time, or locks that are blocked by all read threads and other write threads when the write thread is accessed. Read-write lock in two, divided into a
OverviewThe mutex blocks all other threads attempting to enter what we call the critical section. This critical section typically involves access or updates that share one or more data by these threads. A read-write lock is used to read a reading
What is a read-write lockIn peacetime, our common synchronized and reentrantlock are basically exclusive locks, which allow only one thread to access it at the same time, even if it is a read operation. The read-write lock maintains a pair of locks (
The preceding section describes the synchronization object-mutex in Linux, and the synchronization object-read/write lock in Linux.
If multiple threads read resources at the same time, there will be no competition or resource inconsistency.
This section is mainly about the implementation of read-write locks.As mentioned in the previous section, Readwritelock appears to have two locks: readlock/writelock. If it's really two locks, how do they affect each other?In fact, the realization
In addition to Spinlock, the Linux kernel also has a spin lock called arch_rwlock_t. Its header file is Qrwlock.h, contained in Spinlock.h, which is called "Queue read/write lock" in the header file. This lock implements a read-write lock using only
Simply cache the system: when the thread is fetching data, if that data exists in my memory, I return the data, and if it doesn't exist in my cache system, then go to the database and return the data and save it in my cache.This involves reading and
A frequent requirement of thread security is to allow concurrent reading but not concurrent writing. For example, this is true for files.
ReaderwriterlockslimIn. NET Framework 3.5It is provided to replace the previous"Fat"Version"Readerwriterlock"
Rwmutex: is a mutex-based read-write mutex, a goroutine can hold multiple read locks or a write lock, at the same time can only hold read lock or write lock
Data structure Design:
Type Rwmutex struct {
w mutex //Mutex
Writersem
I. OverviewA read-write lock is similar to a mutex, which protects the shared resources of a critical section! The mutex only allows one thread to enter the critical section at a time, and the read-write lock has higher parallelism than it.
The last tool in the lock is introduced from this section: read-write Lock (Readwritelock).Reentrantlock implements a standard mutex, which is the notion that only one thread can hold a lock at a time, or the so-called exclusive lock. This feature
Linux thread synchronization (3)-read/write lock, linux thread
I. Overview
The read/write locks and mutex functions are similar to that of shared resources in the critical section! The mutex allows only one thread to enter the critical section at a
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