Why Doesn't Go's Mutex Support Recursive Locking?

Recursive Locking in Go

In Go's sync package, the Mutex data structure does not support recursive locking. This means that a goroutine cannot acquire the same lock multiple times in a row. While this may seem like a limitation, there are strong arguments against implementing recursive locks in Go.

According to Russ Cox, a member of the Go development team, recursive mutexes are fundamentally flawed because they compromise the guarantees that mutexes are designed to provide. Mutexes protect invariants, which are essential properties of a program's data structures. When a goroutine acquires a mutex, it assumes that the invariants are preserved.

However, in a recursive mutex, a goroutine can acquire the same lock multiple times. This creates the potential for breaking the invariants, as the goroutine may unlock the mutex and modify the data structure before re-acquiring it. This can lead to unpredictable and potentially erroneous program behavior.

Cox recommends redesigning code to avoid the need for recursive locks. In most cases, it is possible to write code that operates correctly without requiring recursive locking.

If absolutely necessary, there are workarounds that can be used to simulate recursive locking in Go. However, these workarounds are not supported by the Go standard library and should be used with caution.

The above is the detailed content of Why Doesn't Go's Mutex Support Recursive Locking?. For more information, please follow other related articles on the PHP Chinese website!