互斥锁
最后更新于：2022-04-02 04:13:31
[TOC]
## go 没有重入锁的解决办法
bad
```
func Withdraw(amount int) bool {
mu.Lock()
defer mu.Unlock()
Deposit(-amount)
if Balance() < 0 {
Deposit(amount) // 在已经上锁的情况下在调用Deposit会出现死锁
return false
}
return true
}
func Deposit(amount int) {
mu.Lock()
defer mu.Unlock()
balance += amount
}
```
good
```
//降低函数的颗粒度
func Withdraw(amount int) bool {
mu.Lock()
defer mu.Unlock()
deposit(-amount)
if balance < 0 {
deposit(amount)
return false // insufficient funds
}
return true
}
func Deposit(amount int) {
mu.Lock()
defer mu.Unlock()
deposit(amount)
}
func Balance() int {
mu.Lock()
defer mu.Unlock()
return balance
}
//拆成更小的函数
func deposit(amount int) { balance += amount }
```
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