Golang：互斥锁已保持太长时间后出现恐慌

Question

I am trying to figure out what is that is making my program hanging, most of my locks shouldn't be held for more than 200 ms. (actually much less!)

I want to create two new functions (Lock() and Unlock()) so that Lock will have a timer that will panic if Lock has been held for more than 200 ms.

This is my current attempt, but it doesn't work, any hint?

type ShardKV struct {
  lockChan chan bool
}

func (kv *App) lock(reason string) {
    kv.mu.Lock()

    f := func () {
        fmt.Println("PANIC: ms passed")
        select {
        case <- kv.lockChan:
            //
        default:
            panic("PANIC: " + reason)
        }
  }
    time.AfterFunc(time.Second * 10, f)
}

func (kv *App) unlock(reason string) {
    kv.lockChan <- true
    kv.mu.Unlock()
}

Answer 1

Your lock function waits for 10 seconds befor calling the f function which holds the select statement, a simpler way of achieving what you are trying to do might be this:

func (kv *App) lock(reason string) {
    kv.mu.Lock()
    select {
    case <- kv.lockChan:
        //
    case <-time.After(time.Second * 10):
        panic("PANIC: " + reason)
    }
}